Why do people talk down about WWE guys jumping to TNA?

When Austin, Foley, Jericho, HHH, Mysterio, Benoit, Eddie, Malenko, Saturn, William Regal, and others started out in WCW and ECW back in the old days. I mean what was people like Christian suppose to do, leave WWE and quit wrestling to sell vas? Seriousily it's been going on forever. Guys leaving one company and going to the other. So why is it a bad thing for people like Team 3D or Kurt Angle or Christian or Booker T to go to TNA. WWE collected rejects in the past. But I think what I can agree with is TNA needs to push their own talent not people who have been everywhere else.