I have heard this claim before but I find it unconvincing. I have given up support of movements for which activists have acted cruelly or otherwise immorally. Obviously one person doesn't represent a movement, but if I only ever see immoral people leading a movement, that will form a basis for my opinion of the movement.

My observation of these activists is usually that they seek attention at any cost. They will hurt people to achieve that attention. Worse, I don't even think it's about the movement. They just want the attention personally. Others in the movement tacitly condone this behaviour.

I think the most frustrating part of this is that they claim it's to raise awareness. Who among us has not heard of global warming? Who has not heard of data privacy? The reality is that they're not getting the public support they desire because people just don't agree with their goals or beliefs, not because the public is "unaware."