A criminal is a rigidly-defined adjective meaning an entity which breaks or broke laws.
An activist is a rigidly-defined term meaning an entity which acts to further some idea and bring it to public perception.
A hacktivist isn't well-defined, but we'll assume here that it's a form of activist.
Now based on this, the Anonymous and Lulzsec hackers were hacktivists, at least according to their own statements of their intent. They also were criminals, at least according to my reading of the laws of the US. Now, what you may be looking for is whether they were ethically good --- but don't conflate lawfulness with morality, that's worked out poorly in both directions.
But of course, you acknowledge that this is a horribly simplistic view of things. Even DnD got this, after all (clearly Anon is Chaotic, and whether it's Neutral or Good depends on whom you talk to).
So perhaps you might say "I don't believe Anon's actions were for the good", or even "weren't well-intentioned", but please recognize that passing judgement beyond noting the factual statement that they are criminals, is a personal judgement. Not that personal opinions shouldn't be argued, defended, and spread --- just that they should not be conflated with fact.