The danger is honestly pretty minimal for people who are aware they have photosensitive epilepsy; those who are prone to it but unaware of it are not likely to heed warnings even where they exist since they won't typically perceive the risk until after experiencing it.

It takes several minutes from triggering exposure to actual seizure onset, so those who know of their susceptibility have time to stop exposure and make sure they're in a safe position if a seizure does come. There are many ways of mitigating the seizure risk by stopping exposure, closing one eye and facing away from the light source, keeping screen brightness at the lowest level you can still easily read, etc.

That's not to say I think warnings aren't useful, but the intensity of many of the warnings people use is disproportionate to the actual risk and can cause people to be much more worried than necessary IMO. Google et al really need to stop messing with videos and such via AI without any sort of notice or warning for a whole host of reasons, including broader non-epileptic photosensitive since becoming intensely nauseous or getting a migraine over it is still pretty annoying.

tl;dr I think the warnings are a good idea, but maybe a little broader and less "OMG the epileptics are gonna all die". And fuck companies silently manipulating content they didn't even produce with AI in general.