You're on a website chock full of users trying to make money by selling stuff. Of course they're going to be pro-selling stuff, even in sub-optimal closed-source forms.
MIT licence is pretty popular here for exactly that reason.
You may have avoided downvotes if you'd couched your argument in terms of licences. Perhaps.
The other thing that surprised me is the marked shift according to timezone. Right now, noon at GMT-3, I see upvotes for my opinions. However, as noon moved to the US West and mid-Pacific, a steady flow of bad karma hit my comments.
There is a master's or doctoral thesis in there somewhere waiting to be extracted...