Why All the Hate?
Where to begin? Some would argue that Metallica's problems began when they released "The Black Album" (which was actually a self-titled album, but you get it). That's when they became a huge rock band, as opposed to just being that metal band your creepy cousin listens to in his conversion van.
It got exponentially worse with the release of Load and Re-Load, the band's twin alt-rock albums that had the distinction of being absolutely reviled by "true" fans while also selling like crazy. It's around this time that they cut their hair also, making them infinitely more employable in the eyes of companies like MTV.
And your wedding reception.
That's not very metal! From that point on, basically every Metallica release has been met with reminiscences about the days when the band and their music mattered.
Oh, they also, for all intents and purposes, killed Napster. I can't find it in my Internet pirate heart to defend that, but by all means, let's talk about that music.
Why They Don't Deserve It
Metallica was doomed to have a shitty second half of their career no matter what. When they started out, they were kind of a new thing. They didn't invent heavy metal or anything, but they definitely played it in a way that most bands didn't, and it resonated with people in a huge way. They stuck to the same basic formula for three albums, four if you count the one where they protested the death of their original bass player by completely removing any semblance of bass on the first album his soon-to-be-long-suffering replacement, Jason Newsted, had the honor of "playing" on. But shit, sometimes bands and musicians change, you know? David Bowie used to play folk songs on an acoustic guitar. Billy Joel used to be in a rock band. Dr. Dre was a woman.
"Things ain't the same for gangstas."
So Metallica used to be a metal band, and now they're just a band. Big hairy deal. It seems worse than it is because the genre they come from tends to breed fans who listen exclusively to music in that genre, so anything they do from now on will disappoint those people. Hence the howls of protest that greet every single thing they do. They're still a fine band otherwise, even if St. Anger was the worst thing made by anyone ever.
Why All the Hate?
Scientology is one of the most hated "religions" in the world. Tom Cruise, even if it's unofficially, is the face of Scientology. It's really that simple. Until Will Smith finally caves to pressure from Doug E. Fresh and books his own cruise aboard the Sea Org, Tom Cruise is the biggest star Scientology has in their stable. Unsurprisingly, people hate that.
To make matters worse, the dude is just kind of strange, and he only seems to be getting stranger as the years go by. Being way into any religion will give anyone a patina of crazy that the common folk just don't have. Tom Cruise isn't immune to that just because he has a successful acting career and the whitest teeth in the game.
Basically, in the eyes of a lot of people, Tom Cruise is your garden variety religious wacko and not much else.
Why He Doesn't Deserve It
Man, is Tom Cruise the only Scientologist? I guess I just don't see what the man's Thetan count has to do with his role in my life, which is to entertain me in movies. He's fucking great at that. Have you seen Magnolia? Scientology be damned, that's a good flick. And Tom Cruise is a good actor. A great actor, even. When I see his name in the credits, I feel a little bit better about that movie. He's like the Tom Hanks of guys I'd never want to hang out with.
And see, that's the thing. I don't have to want to hang out with him, I just have to want to see his movies. That's all Tom Cruise really owes me in life. If he's a shitty boyfriend and/or husband, maybe chicks should stop marrying him. It's really none of my concern. I doubt anyone would encourage Katie Holmes to hitch herself to my e-meter either. If he talks too much about Scientology, fight back by not being a Scientologist.
But for my money, nobody plays a World War II Nazi with an American accent or a Caucasian samurai quite like Tom Cruise. No couch-jumping meme is ever going to change that.