This is begging the question.
DDoS is not terrorism. Terrorism is "the unlawful use of violence and intimidation, especially against civilians, in the pursuit of political aims."
Inconveniencing a people, by taking down a website is not violence or intimidation.
Without that tenant, everything you've argued on this thread is a moot point.
Keep in mind who you're defending here. The site in question doxxes trans people so they can be harassed and sent death threats. That IS terrorism.