How to remove -rep from random strangers?

Maybe someone doesn't like you and that's why he gave you that -rep? Is it legit?

Well, you were trying to lowball his offer. But still that's not a valid reason to give -rep.

If the person won't remove it themselves, all you can do is wait for Support to get around to it, and I gather that there are only one or two mods able to handle it with quite a backlog, so it might be a while. Fortunately you've got enough positive rep that no one should be too worried about dealing with you in the meantime.

In my opinion, lowballing is pretty bad. I won't write negative rep over it, but I will tell them to fuck off.

It's part of the reason I don't care about steamtrades or trading in general anymore. It's all about me me me, and no one cares about anyone else.

Well, you might have to wait for a bit. :P
clicky

Lowballing isn't really a good enough reason to give -rep. Lowballing is too subjective, without knowing how much the original asking price is/was. Some people confuse bargaining with lowballing.

You have to wait. Support at st and sg is like valves, only much worse. Can take a very long time before the mods can feel like doing anything, so you'll just have to wait.

First ask him about it, if that doesn't work support is the only way.