It seems like what you are referring to are forms of ridicule and attempts to decontextualize the issue to transfer the focus from the subject to you.
One might simply name that denigration. Or, perhaps, defamation. One might say: "Stop the personally denigrating comments, and extend to me the courtesy I give to you."
Senators in the U.S. use the phrase, ad hominem, meaning directed at the person, as a high way of saying, that's insulting. Insulting and therefore not productive to friendly deliberation.
It's not ad hominem in the proper sense of being aimed at your principles or view of the matter since it is a distortion of your view, rather than a speaking to your view. There's a mistaken view that ad hominem is always something negative. It's not. If they really address your views, that's legitimate and even helpful to a deliberation that aims at clarifying issues.
The modern usage is vexed by the fact that the understanding of what a fallacy is has largely withered. So far as ad hominem is a rule of good sense, of experienced judgement, i.e., an informal fallacy, then the issue is if they dismiss the matter for the reason of the source alone. That doesn't make sense, since even a fool can say something that is true if only from time to time.
But views don't exist apart from human beings. So one must speak to the one who has the conviction or opinion in order to change the opinion. It's clear, in the cases you bring, that no friendly attempt to change your view is meant. Rather an attempt at character assassination is meant or at thuggish dismissal.