I see your point on how if someone asked you to move, yes. They might have some emphasis though on why don't you goto the floor then if you are going to stand? Not siding with either, just a statement.
I, for one, is one of the main seaters. I love metal, but I don't goto the fashion of headbanging my heart out, air guitaring it *Too me, it's just silly, I play a lot on guitar- mostly metal, but I just don't see the satisfaction with this*, or crazily jumping up and down, etc. I don't think less of the people that do, I just don't do it. Music takes it toll for everyone, and they get into it in their own ways. Edguy, and only edguy was the only one that got me on my feet for the entire thing. The rest of the bands I wanted to see, liked no less, but enjoyed from the pleasure of my seat. I would sing, moderatly headbang, but nothing extreme. I'm not any less of a fan.
If you want to stand though, why not just goto down too the standing floor. Or stand in the aisle, something... It's not that hard of a thing to do.
The earplug comment seemed a little harsh, I wear earplugs too, and I know a lot do as well. Last concert I went too, where stood the whole time *So don't think I can't do it or lazy or what not* damaged my hearing because it was so loud. Never ever goto a loud concert especially metal without them. When you do have a problem with your hearing, and the concert is over, you will slap yourself the rest of your life. I know I am. If you buy a decent earplug, you can hear the concert fine, it just takes the harshness and damaging frequencies out. This lets me enjoy the concert fine, and not have any stuffiness, ringing, or any problems at all after it's over.
The sleeping comment also is judgemental. Some people, my girlfriend, fell asleep yes. She fell asleep during Angra, when it was one at night. After two long days, she was tired. So get off people's back if they are tired. And most bands, except Edguy, Gamma Ray, and a couple others, had extremely boring parts. I am a huge Blind Guardian fan, but I found that their appearance to be rather blah in the concert experience. They sounded fine, played good, but out of my seat - no.
Music's your own thing, it is for everyone. If some sleep, they most likely feel that way about that band. If you saw someone sleep through all 10 bands, then yeah, you're right. If not, enjoy music how you do, and let it be.