Is this voting brigading / shilling or just normal behaviour of groups trying to suppress dissenting voices?
Also, is this part of why semi-noobs think that HN is turning into reddit?
Neither. (If anything, perhaps the assumption of malice on the part of people who disagrees with you is what smells like Reddit)
The dynamic is something like this: The comment gets up-votes because nothing is easier than hating on Microsoft, and down-votes because it isn't actually insightful at all. You can squint at any action by any company in just the right way and make it look like it's part of "Embrace, Extend, Extinguish". The comment essentially boils down to "Microsoft has done bad things in the past, so they're probably still doing them" with precious little in the way of actual analysis.
First for your general question:
I think that people get tired of seeing the Embrace, Extend, Extinguish come up in every single thread about Microsoft.
It's a simple argument that seems to be overused and an easy grab for votes, or to bash Microsoft. If someone brings something new to the conversation by calling Embrace, Extend, Extinguish then I'm game for listening, but most the time it's just. Microsoft is a wolf in sheeps clothing look look they are Embracing. OH NOOOOOO. Open source? They can ALWAYS change their licenses? Runs on Linux? What are they going to do start offering free Windows 10 upgrades on Linux? Extinguish Extinguish!
Microsoft is a huge company, some departments suck and are run by unethical dicks (looking at you Windows 10). Their developer tools have taken some huge steps lately and have had huge success. Visual Studio Code is used by a lot of people who don't like or dislike Windows, some don't even use windows. I'm just kind of done with this argument.
Some comments on the OP:
This particular "Embrace, Extend, Extinguish" argument does bring something newish to the table calling this particular action one of the steps as foretold by our CS prophets on high. The OP gives a new spin and is on topic and shouldn't (imo) be down voted because it brings out healthy conversation (which is the point of reading comments on HN vs Reddit). If this were Reddit it would have been punnier.
Their minions write a lot of blub comments so that the comment count is higher than the voting count of a story which equals to flagging a news!!
Another very visible behaviour is that they very quickly push positive news out as soon as there is a negative news.
If you track HN stories about Microsoft with a third party HN tracking service, you clearly see evidence that unfavourable HN stories about MS vanish very quickly by flagging or overflowing the story with a lot of blurb comments to hide them. And on the same day another often minor but positive news surface and sits on HN frontpage for several hours - and of course flagging all comments that even try to hint the privacy issues with Win10 or anything remotely normal comment that isn't overly hyping their software/service.
I have created such a view and see correlation with stories from MS. But not from Google, Apple or Amazon, nor any other company.
The usual tactics one can see is that a negative story about MS is getting flooded (after x min after they started to react) with many comments. As soon as the story has more comments than upvotes the HN sorting algorithms acts like the story was flagged and puts it of the HN frontpage to page 100+, and put a few flags to the mix and the story vanish pretty quickly. One can also see that MS seem to have a backlog of prepared positive stories. As everytime a negative story hits HN, the negative story is threaded as mentioned plus a new positive story is submitted and upvoted as replacement.
Edit: everyone else can do this too, and can watch these behaviours.
I come to HN to read news and the comments. So I sincerly don't understand why a story with eg 400 upvotes and 500 comments is hidden from me, but being the number one story on HN of that day. I suggest to change the threshold on HN so that either a comment count higher than upvote count don't alter the story position at all or change the threshold to make the site experience more transparent and fair.