And so does my Azelf. I think I mentioned the Entei-Rotom thing before?
Rotom's legendary, right? He's actually pretty weak though, he's just a scrappy little UU poke. Even with his new formes, he probably wouldn't break BL, an average OU at best.
The same goes for Entei. He actually has a very high HP and attack stat - but they cap lower than a lot of OU pokes. His movepool is also terrible, he's legendary, but he's crap. Being one of a kind/legendary doesn't mean much. Think about it. Not all pokes are created equal, and certainly not all legendaries. If a legendary is in OU(or an even lower tier), it's definatly a fair poke.
You could also think about it this way. Some legendaries are UU, BL, OU, and uber, right? The same goes for regular pokes. So they have one thing in common - no one category of pokemon is filled with only good pokes. Hating all legendaries because they're uber is like hating all OU pokemon because they aren't UU. Pretty simple, yeah?