Oh, come off it already. It is clear what he meant, you are just trying really hard to be offended by something.
This was so unprofessional, it's like it was written by a black teenager!
...is that better?
Or is it more obvious now that the original comment was an insult to girls?
No, it was unnecessarily sexist and demeaning.
Yes it was clear the poster was being derogatory to girls. It's also clear you are trying to normalize and justify such behavior. Both are unnecessary.
There are negative traits about both teenage boys and teenage girls. The writing style more closely matches teenage girls in this instance, so that's why the connection was made. Sexism exists in tech but this is not it.
Clearly the poster was talking about the excessive use of `like` which he deems as the typical vocabulary of a teenage girl which is what you're attempting to be upset by. It had nothing to do with teenage boys being significantly more professional than teenage girls, or anything of the sort.