I want to remove this shelf support in my office. It doesn't move with bare hands at least. I think I need to somehow remove the small round thing that is adjacent to the wall mount. My next action would be using a plier to see if that thing moves. Any advice is appreciated before I break this thing. Thanks!
I have pretty much exactly the same shelf brackets.
They wedge in place, and the cylinder is NOT the secret to removing them. It stays put on the bracket.
A light tap from a hammer (preferably after removing the shelf) on the bottom next to the wall standard, going upwards, is the way to get them out.
See if its cousins are more tractable.
I see there are others of this mount type mounted the same way. See if they come out. Usually things like this lift vertically and pull forward. If none of them move then maybe you are right about that peg. But if this particular one is just jammed or bent somehow, you can figure out from one of the others what it is supposed to do, then try to make it do that.