I came here thinking this sounds like she might be getting woke-cancelled for suggesting Israel is pure as driven snow...
Khalifa even urged Hamas fighters to "flip their phones and film" executions horizontally in one of her posts.
Nevermind, she can go fuck herself with a cactus.
If you think military fighters executing civilians is an acceptable strategy, you probably deserve to be among those civilians and see how you like it.
Much has been said about the idea of 'signal leaving UK or EU'. Little has been said about how exactly that would happen.
AFAIK, Signal has no business presence in the UK or EU. IE, no offices, no registered corporate entities. Thus, they (arguably) have no more requirement to comply with UK's or EU's regulations than, say, Iran's or China's or any other jurisdiction where they do not do business and have no presence.
Signal's leadership has a record of giving any regional restrictions the middle finger, so I doubt Signal would voluntarily block EU countries. So that means the EU would either pressure Google and Apple to delist Signal (easily worked around, at least on Android, and soon on Apple too as EU is trying to force sideloading) or they'd pressure ISPs to block connections to Signal (more or less impossible).
If EU tried to do that, it'd just create a giant game of whack-a-mole. And people doing real CSAM shit would just move to even more private distributed systems.