The conspiracy stuff really doesn't make sense.
Both Ivanovic and Torres could have been sent off earlier in the match for a couple of vicious fouls.
Torres was given the second yellow for a dive when there was actually minimal contact, but he shouldn't have been on the pitch anyway.
Valencia was actually also given a yellow for a dive and there was far more contact, yet nobody is complaining about that decision.
David Luiz handled the ball in the penalty area and nothing was given.
The winning goal
WAS offside, but it wasn't an easy offside to give at the speed and direction he was moving, and the fact he was comfortably in an onside position by the time he received the ball would make it harder to tell it was offside when the ball was played.
So in United's favour we have an offside goal given, and against them we have a penalty not given and two Chelsea players being on the pitch for a lot longer than they should have.
On balance you could argue that more went against United in the match than for them, and yet we have the usual conspiracy theory stuff.