Should children of people who belong to cult organisations like westboro baptist church, KKK or MAGA be removed for their own safety?

Good question... On one hand that will only alienate and escalate the parents further, and perhaps the children as well if the indoctrination already prepared them for that possibility. On the other hand, they are definitely in danger.

And where do you draw the line? Do you stop after MAGA? Move on to all Catholics, all religious people, flat earthers, antivaxxers?