I'll preface this by saying the first images found under "Kanye West" were pictures with Kim Kardashian, which really doesn't bother me.
Anyway, the funny thing about these two men is that they've committed no felonies or despicable acts, (okay, maybe Kanye calling out President Bush on NBC), but they're extremely disliked by the majority of people.
Two personal friends have said that West is actually a decent dude, albeit they didn't have an hour-long conversation with him. LeBron does charity work and is trying to better the area he is from, even though he makes decisions like holding "The Announcement" in a wealthy suburb in Connecticut (thanks ESPN).
James' game is criticized because he's not in Kobe Bryant's mold, but it's your fault if you don't accept his entertainment value and greatness.
Mr. West has a distinct music style that turns people off, especially in the case of 808s & Heartbreak, a flop for his standards as well as not being his style. One could say that's comparable to James when he tries to finish fourth quarters.
The greatness of both men will be fully appreciated when they're gone, unfortunately.