But, that's the point. In the OSR, you don't have a 600 pound gorilla leading the pack. All you have is home-brew. New "official" material hasn't been made in over twenty years. Good grief, it's getting very close to the point where WotC has published D&D longer than TSR did. So, of course you see lots of experimentation. That's all you have.
When your hobby is nothing but home-brew, then, well, home-brew is what you have. When your hobby is massively dominated by a single publisher, any single book probably outselling all home-brew options combined, then of course official is the way to go.
It's not that people are more judgmental about 5e home brew, it's that, like OSR, the overwhelming majority of the material comes from a single source. The only difference is that in OSR that single source is home-brew whereas in 5e, it's WotC.
The old canard that home-brew is this source of superior material if only the majority of players would realize it has been around since the earliest days of the OGL.