Does anyone here know how people take magnetos helmet off when they try to get into his head or punch him or make him more vulnerable? It is said he does not need to motion his hands in order to control objects so why the hell doesn't he just use his powers to keep it on his head? what the hell is this trickery? got his damn head scorched off by cyclopse in ultimatum cuz his magnetism failed in the most important moment.

Well.... that was the Ultimate Universe soo.... that's enough said on that.  However in mainstream Magnus has been portrayed as sometimes needing his helmet and sometimes not.  I avoid Ultimate like the plague except for Cap so I'm not sure the extent of his powers in there, but in the mainstream he has electromagnetism and when he's being written as not needing his helmet to stave off telepathic assaults, it's said he controls the electric signal's in his brain and that, combined with his willpower, is enough to fight of telepaths like Xavier and Jean Grey so its not a big worry to him.  But honestly, his helmet's not snatched off too often and I've read all his appearences in Uncanny X-Men up until he joined the group on Utopia and I don't remember him ever having it taken off.

He can hold the Helmet in place using his magnetic powers...
 
If his concentration is interrupted, anyone who can grab the helmet can pull it off...
If not, then someone with super-strength might be able to rip it off, or rip his head from his body...