I was trying to go by the prevailing sentiments in fandom, but of course that changes depending on where you go. A lot of people are certainly very down on Dumbledore, and I usually find that few are willing to defend him.

I don't know anyone in fandom who hates Lucius, though I'm sure such folks exist -- in any case, he has a strong contingent of active fans.

It's true that Draco is hated by some, but he also has a vast fan following to counterbalance it.

I hesitated with Percy, because I do know a lot of people who like him, but he's still a niche interest, and I also hear a lot of negative talk about him.

I tried not to take my personal likes and dislikes into account. Obviously, I'm fond of some of the characters I've listed. ;)