No. I would feel like a bit of a douche telling people not to shorten it so I'd either get over it or choose another name. I'm super fussy with names and every part of them though. Like, I liked the name Jonas but would never use it because the first part sounds like Joan and I don't like that name.

My cousin is Tom and had the name lengthening problem. His name started being "Just Tom".
Same here. Our little guy is Tom, and we named him that because that is exactly what we planned to call him. He gets Thomas, Tomo, Tommy, Tomcat Can't win! It drives him crazy. It's JUST TOM ok, he often says.