How is a closed beta anything out of the ordinary? They know they would only get tons of shit flinged at them if they publicly released something beta-quality, even if clearly labeled as such. SD users can be a VERY entitled bunch.
I've noticed a strange attitude of entitlement that seems to scale with how open a company is - Mistral and Stable Diffusion are on very sensitive ground with the open source community despite being the most open.
If you try to court a community then it will expect more of you. Same as if you were to claim to be an environmentalist company then you would receive more scrutiny from environmentalists confirming your claims.
That's… not really relevant to Stability AI at all. SAI isn't "claiming" anything. They are show, not tell (well, mostly). They give a technology away for free the likes of which everybody else keeps very tightly locked behind SaaS. Then people bitch about said free technology.
