Why suddenly are all of the blue states doing this BS? What is going on and what control is this affording the government?

Lobbying from Meta. They do not want to do age-verification themselves (and pay for it).

See the actors behind this here (Meta is a big one): https://tboteproject.com/

Meta is behind a huge amount of it, they have funded the majority of these

Meta is lobbying with millions for it.

Blue states: paternalism over your property, liberty for your body

Red states: paternalism over your body, liberty for your property

except for during covid, where there was a weird reversal.

I don't even know if that was much of a "reversal".

Blue states were paternalistic over both your property (business and social gathering shutdowns) and your body (masking, social distancing enforcement), while red states (particularly Texas, Florida) were very laissez-faire for both.

What's perplexing about this is that research has generally correlated higher amygdala activity (fear/worry) with political conservatism, and lower amygdala activity with political progressivism, but in this case, the effect seemed almost inverted.

In that case, I imagine that the response of mask mandates wasn't out of fear but was done do to the obvious benefit in controlling a disaster. The anti-masking movement is also I suspect a fear response. People are afraid of change, especially extremely visible change

Fear of infectious diseases is inversely correlated with testosterone levels, and so is liberalism.