It depends on the context. I used to say it quite often when people got angry with me for saying something.

When debating informally, I take it to mean "I have no answer to your last point so I'll just ask you to reread the ones I've already made and then maybe you'll get it. And p.s. I WIN! "

Rather off-putting, as it spoils a good exchange that might've ended in agreement, with both sides wiser than before.

Yes it's like 'Not being rude but...'
One of those insults where somebody's trying to excuse the fact that's exactly what they're being.

@RedBaron i think the point trying too be made is there opinion does not neccessariy agree with the person who posted the question. or the comment to a question maybe slightly controversial and by putting just saying they do not wish too have there comment taken in the wrong way