if you protest against a politician trying to approve a law that fucks everyone for the benefit of his personal business

Even in this case, going after them as a person, instead of protesting against the law itself seems counter-productive. If I make an argument and someone then calls me stupid, it's not going to change my mind, nor anyone else's who agrees with me. It's just makes it sound like they simply don't have a better argument. It's maybe a bit different when the personality flaw in itself is the issue, as is the case with Trump and lying for example, but if one then starts making fun on his small hands that just makes them look petty.

However, I still want to aknowledge, that humans are social animals and such public ridicule has been a powerful weapon throught the ages, so even though I personally don't want to act in this way, and in my ideal world no one else would either, it is still possible, if not even likely, that such ridicule is very effective. Then again, shooting them is effective aswell, but I don't want to live in a world where we solve disagreements that way.