I can understand that if you read my comment as if I intended to be insulting.
I'd like to point out that: I did not intend it to be insulting to the authors, for 2 reasons:
1) Nobody knows everything; I'm responsible for works which I do not go into detail with. For example, my reports include: Render Architects, Gameplay Programmers, UI/UX Design and things I conventionally understood such as Backend Development/SRE. -- If I spoke on a rendering topic it would be high level, this does not mean I am bad at my job.
2) The way in which this was presented is either: Highly media trained (IE: DO NOT GIVE ANY SECRETS AND WE WILL NOT TELL YOU WHAT IS SECRET WE WILL ONLY EDIT IN POST), which is a situation I've been in before actually, or the person presenting is, like me, managing a team of specialists that she does not go deep technically with.
I want to be clear: I do not think less of any of the people who presented this, I do however think less of GitHub the organisation for presenting this marketing without very much substance.
The crux of my comment was precisely this, certainly not an attack on any individual.
I even tried to acknowledge my potential bias towards sexism, racism (and perhaps also the valley accent): however, on reflection, I genuinely believe that I would have scolded a caucasian male significantly worse for presenting in such a way. I definitely pulled punches based on ethnicity and gender; which is also a form of racism/sexism - just in this case it actually benefits the video and its presenters.
The reason I even consider that they do not know the subject matter in depth was that the conversation stemmed almost entirely on what the presenter was seeing, as if they were finding things they recognised. Like when a person who has built computers opens up a server and recognises RAM, or USB ports. (something I have seen often in my career when non-IT folks get curious when people are working on servers). The second reason is typically engineers love to explain reasons. The why of a thing is usually much more thrilling to discuss and that wasn't talked about at all. IE: why is it clever to have an external thunderbolt ethernet controller, why is it clever to have these machines housed in sleds instead of racking the whole device.
The kinesthetics of how they're just pointing at fans, power and sliding it in and out of the chassis just reminded me of how I was when I got my first server hardware and started playing with it. It lacks the familiarity I would expect.
I hope you understand my position, it's not intended to insult or offend, we all have value of course and I was just uncertain if Github had put her in front of the camera because she represents a high position and doesn't work with this daily; which in my opinion reflects poorly on github, not on her.
It is (genuinely!) good that you did not intend malice with your post. And being aware of sexism, or any other kind of stereotyping/discrimination, is definitely a good start. That said, just because you did not mean to be insulting does not automatically preclude you from coming across that way. While we all make mistakes, and I assume from your comment that you wish to avoid them yourself, I think what your reply here really shows that you did a poor job at expressing what you really wanted to say. This is unfortunate, because it's actually pretty easy to rephrase it to not come across poorly.
You–and this is a fact–noted that the video does not have much technical content. It's kind of a marketing piece, really. A lot of people here (myself included!) would have probably wanted a deeper dive into the technologies involved. Here are some examples of how you might rephrase to convey that:
"It's interesting to see that they got this working, but I have to admit I'm kind of disappointed by the video. There's not a lot of detail as to how this works. I was hoping they would explain the Thunderbolt adapter, at least." (It's rarely a bad idea to be courteous and polite, especially when you start a comment. This conveys your feelings and where you feel the video falls short. The work itself, rather than any people involved, are brought up.)
"What's with the big Thunderbolt network controller? Anyone know what's up with that?" (Invites others to respond if they know the answer. Perhaps even the author or someone closely related! They often browse the internet just like you.)
"This is really just a marketing video :/ It's kind of stupid that they don't actually explain anything that's going on. I hate companies that keep their cards close to their chest." (This has a much stronger opinion in it, and your idea of what they should do to fix it, but it directs it at GitHub, not the people in the video. GitHub is a lot of people but not one person. It's hard to offend a company.)
"Why did GitHub make this video? It has no technical content and makes it seem like these women are not involved in the engineering process. Why bring out the director of this team if you won't even let her say anything about the actual work she did?" (This is a very strong opinion. If you're careful you might be able to play it, but do note that the women in the video may not appreciate you speaking for them about how the video portrays them.)
On the other hand, you said, and I quote, "I got the impression that the guide didn't know anything about what they were talking about w.r.t internals or how it's used". Do you see how this directs your criticism at the people in the video? There are plenty of reasons why they might not go into detail, many of which are out of their control or not relevant. You might have the "impression" that the guide doesn't know what she's talking about as opposed to, say, actually not knowing what she's talking about, but if you go up to someone and say "I get the impression you're stupid" that's basically saying "I think you're stupid" or "you did something stupid". That's not nice, regardless of how you feel about it. From your second comment, your annoyance has nothing to with the people, so why bring them up? Direct your criticism at the thing you care about.
I think a big problem is that people often realize that what they're about to say is difficult to express and can be a sensitive topic (women in tech, here). Unfortunately, saying it anyways and then ducking under "this is hard to describe! I am not being discriminatory! I would say it to white cishet men too!" doesn't actually really help. First off, why would you say it to a white cishet man? Your comment, in a vacuum, doesn't have any sexism in it. It just sucks in general. You probably shouldn't be going around telling men that they give you the impression of not knowing what they're talking about, either! But when you do bring into the picture that women are the target of these comments more often than not, I think you should demonstrate a little more tact. Read it a bit more closely to see who the criticism might be aimed at, and soften or clarify as appropriate. Or ask someone else you trust to help you out!
That's a different claim altogether. You're right about how their phrasing directed criticism at the presenter rather than entirely at the company, so you should steer clear of strawmen while you're ahead.
I got the same impression, and I think it's a fair critique of the video and the presenter. OP simply acknolwedged that unconcious bias may be affecting their judgement, for better or for worse.