I'm going to assume that despite your words you meant "obviously fallacious" to only refer to part of the first paragraph of the comment you are responding to. That would make your argument much stronger.

problem with having the majority of any discussion dominated by 'ethics'.

Obviously fallacious arguments are getting voted up heavily because they defend PUA and attack ethics

Assuming your intuition about why people are voting as they are is correct, saying that something shouldn't dominate is hardly an attack against it. The statement that it shouldn't dominate was justified with a reason - a defeasible reason that does not apply in all contexts. When people can agree on facts, ethics based conversations can flow.

When people make ethical condemnations of caricatures that don't exist and refer to them with labels used for their political enemies, forcing the accusers to detach their claims from their subjective values hopefully keeps them honest.

Obviously fallacious arguments are getting voted up heavily

Arguments aren't voted on. Posts are. Posts with multiple aspects. "It'd be kind of redundant," is wrong. Obviously fallacious, as you said. " If you are going to rape people then you don't need PUA," would approach being a non sequitur except for that the post responded to was so detached from reality that it may have had to have been said in that context.

The rest of the post is good, and worth upvoting. You are overconfident in attributing the worst possible motives to those voting for a post you disagree with.

One final distinction: the argument that ethical considerations should not dominate discussions is an argument against discussing ethics to a certain extent, at most it attacks discussing ethics, and the contextual posts show that ethical considerations were not being disregarded. This is in addition to the argument that there should be somewhat less of something being a mild one.