Are they? I watch YouTube on Firefox all the time, seems fine on my machine.
I think maybe 5+ years ago there were some performance issues caused by YT relying on features that were only implemented in Chrome, but I don’t recall having any issues wrt that for years.
I’m too lazy to look for any of their documentation about this, but it would be pretty bold to believe privacy or processing claims from OpenAI or similar AI orgs, given their history flouting copyright.
Silicon valley more generally just breaks laws and regulations to “disrupt”. Why wouldn’t an org like OpenAI at least leave a backdoor for themselves to process API requests down the road as a policy change? Not that they would need to, but it’s not uncommon for a co to leave an escape hatch in their policies.