Does calling out and insulting other Y/A users advance the cause of Alternative Science?

Calling people out that constantly promote very unreasonable or harmful ideas could be justified although that doesn't need to be done in an insulting or abusive way.

For example you could tell someone that their belief in ghosts was completely irrational without making belittling remarks regarding their age, gender, ethnicity, race or sexual preferences..

How could you possibly insult a YA user?

People who hate hearing the truth often lash out insults. Especially here, also non believers.

I'm not sure if they hope to dumb down others like a cult, or just be mean.

Sometimes perhaps yes. Exerting some form of minor violence can perhaps send a signal to some people.

You have to realize that being very polite does not always prevent lies from being said, and bombs to fall.

It is likely that you have in mind English Guy, and his often repeated (and deleted) strange questions. He actually said "I only tried to say I still support her ...", followed by some ranting of a sexual nature.

Hell No, it sure as hell don't. It's just more evidence against anything paranormal or supernatural. English Gay should be removed from YA because he's a hateful racist, misogynist, homophobe, etc. slanderer. He claims skeptics are denialists, but the truth about that is that he's a denialist of Science, Logic and Truth. There are a few trolls similar to him but on a smaller scale. 

It does not.

Pointing out flaws in weak theories (which is not the same as being insulting to the proposer) so that others are not misled does help advance the understanding of real science.

No, but that's often all alternative science believers have. It's not as if they have any actual science. 

irrelevant, as both are violations of the guidelines

The personality of anyone who asks or answers questions here is irrelevant to the controversies of science. I will sometimes point out that X has misrepresented the facts about a particular question, but I avoid pointless ad hominem argument.

“Never argue with a fool, onlookers may not be able to tell the difference.”

― Mark Twain

I don't recall who posted that quote here and for too long I didn't pay attention to it. When a troll calls you out the best thing to do is follow Mark Twain's advice. Do not answer back, ignore them, and make your point in a straightforward answer. When you answer a question here you're not only answering only for the asker, but for everyone interested in the subject. Call out the subject matter, not the insults of a troll.