I think most Gaga and Madonna fans that internet stan either like one artist or the other. That's probably more fan related than "them" related. In the real world, if you like Gaga you probably like Madonna and vice-versa.
The question is, why little monsters hate Madonna so much?
Not all of us hate Madonna... at all... look at my sig. Look at the fact that Madonna is actually more played than Gaga on my now 6-month-old last.fm account.