But standing against someone and pointing out why you disagree I think is quite in the spirit of Stallman himself.
With that said, I don't know the extent of the abuse that Stallman has received from others, but its not obvious to an outsider what the abuse is. Some mocking over a rider? You should hear the abuse I've gotten over some of my haircuts.
I will say that while I disagree with RMS I do think his influence has been large and positive for most of his career. I don't think he's a particularly good spokesperson, but he makes up for it in other ways. I've even listed RMS as one I think is on the short list of potential Turing Award winners (http://news.ycombinator.com/item?id=2305496).
I stand against Stallman, but I'm glad he's there to stand against.