It's not toxic because I disagree. I think there are legitimate reasons for people to raise their concerns, and I personally have some issues with the initial demo that I have hopes will get ironed out. However, the attitude and tone of how people have voiced their opinions has in many cases absolutely reeked.
It's toxic because it's rude, insulting, and actually has been personal attacks in many cases. The game's been called awful, stated to be not worth $5, the testers have been called sycophants and worse, people have called the UI developer an amateur, insulted the renderers, etc etc etc etc.
I do not think it's inaccurate to say it's entitlement when this is a beta demo that nobody has yet paid for. Like, for heavens sake, people are acting like Adam has already taken their money.
Toxic is a useful shorthand. I am not saying that nobody should criticise but I do not think it is unreasonable that people be polite and respectful.
And yes some users have attacked back in the opposite direction too against the critics.