You're ignoring the part where Trump says he would make himself dictator. I'm not willing to risk that just for the sake of one man. That's a strange type of logic for me. Better to put pressure on Harris and embarrass her. She needs people to like her.
And honestly, the only people who see Trump and Harris as the same are people who've already figured out that they won't be affected by either of their policies. So it's okay for them to focus on a single issue.