He didn't say "ugly", he said they're rather "cool" than attractive.
But still, stanning aside, the four of them look beautiful to me, you must be blind to say otherwise.
& Obviously, international fans agree. They don't fit the Korean beautify standards (Yoona always ranked 1st, who wants to look like that ?

) which is fine, but that shouldn't affect his opinions.
BigBang aren't exactly that handsome either (esp. compared to other male idols) yet I don't see him calling them unattractive, just because they're more successful than 2NE1 in korea, and don't get dissed as much.