I'm going to repeatedly call out a coworker for gross personal habits
Oh no that sounds serious. What is he doing that's so gross?
I can't stand him eating his food with his hands
If you find it so distasteful, you should speak to your coworker about it.  Pointing it out in front of everyone else just serves to embarrass this colleague of yours, which is wrong.  I'm sure he'll understand if you just tell him how uncomfortable it makes you.
I'm doing it because I want to embarrass him. I want to make him feel bad because he never throws away his lunch tray. It's making me mad at him.
It is understandable to be frustrated but embarrassing someone in front of others can make them feel defensive and not likely to listen to you.