The perception is that they are agents provocateur and not honest debating opponents. Repeating arguments which have been shot down over and over again is not the mark of an honest debater.
There are a few exceptions though. I think Mr. Rogers is not an Obot, I think he simply cannot distinguish his own emotional preference on the issue from what is actually true.
As for "making stuff up", I think this is less a case of people being intentionally misleading and more of a case that they are misinformed and then repeat that misinformation. It has happened to me once or twice. Once the facts are pointed out to me, I correct my miscomprehension.
Here is a typical example of this:
Sherman Logan argues that natural born is identical to native born.