This guy hit it right on the head.
What everyone here is doing is seeing the crowd singing as a lack of effort, whereas when you leave a LP concert, sure you feel great, but you don't feel as attached to a given song as you do when you get to actually take the reigns and sing it as if you were there on stage performing the song.
We also don't see the other bands that do that too, such as Metallica. We just chose to attack MARS because they seem to be gaining popularity in mainstream music. You're entitled to opinions, but you shouldn't be entitled to completely destroying someone else's, or for just taking one person's opinion and taking is as their own (I've seen a lot of people taking Mark's exact words when flaming me in the chat).
Just saying, based on my experiences. /2cents