Don't paint with a broad brush. There are flippers who do things right and actually FIX the houses they buy, legitimately.
Many though do nothing but speculate and drive up prices for no good reason. Buying them up, to create more scarcity.
Hey if that's what they do, so be it. There are no guarantees in life. Again, I will not feel sorry for anyone who loses his shirt when housing collapses in certain areas.