Me and Britney
I think we all have read the whole thing. It's the fact that's a backhanded compliment. Even if you powder it with compliments, she still blatantly said "Adele is bigger than me, how come nobody says anything about it?" when people have been making fun of her weight as well, for years.

GaGa could have said "other pop-stars are larger than me" but she called out Adele and said she was fat, even if it was supposed to be in a good light. It was rood. If you did that in your group of friends and said, I love that I've gained weight, but why isn't Michelle over here getting made fun of, she's bigger than me"... you have to understand that may make the other girl feel pretty bad.

It's a simple situation where GaGa (maybe accidentally) called someone fat.