I don't see the big issue. The phrase "big boobs" alone is not sexist. If it had said "the only good thing about women is big boobs" this would be a different

I don't see the big issue. The phrase "big boobs" alone is not sexist. If it had said "the only good thing about women is big boobs" this would be a different case, but it doesn't. The phrase alone means nothing and anyone calling it derogatory or celebratory is simply projecting.