If you ever come across one of these demonstrations and feel up to it you can ask a random activist what they are protesting. You may be surprised to find out many activists don't really know much if anything about their supposed cause other than what the current desired narrative pushes. Many of them don't even know what it is they're there for, just that there was going to be a demonstration and they wanted to be part of it.
I would suggest that the OP is suggesting that because the terrorist organization supports palestine and engages in these activities, the label is more controversial than other organizations such as irish unification, communist revolution, drug cartels, white supremacy or neo-nazism organizations that are also labeled as terrorist groups without much controversy.