What changed is that they made the text clearer, that ESTA approval doesn't guarantee entry and decision is made by the border officer and adding a note that wrong information may lead to incarceration.

Those notes weren't "needed" before as that was rare, while theoretically the rules were the same, but seem to be handled stricter now.

This is still far from a "proper" travel warning.

https://www.auswaertiges-amt.de/de/service/laender/usa-node/...

We've had multiple examples in the last few weeks of Australians being detained and having phones/laptops searched for no legitimate reason e.g.

https://www.smh.com.au/traveller/travel-news/an-australian-w...