Nothing like rational explanation, and I would agree with the spirit of this. However, to ignore human frailty is wrong of us. I think the fact that our players don't mob the referee for decisions is laudable, but I cannot help feel it costs us at times. But generally, yes it must be true that the more pressure you put on defenders the more likely it is that they will concede free kicks and penalties.
I certainly don't subscribe to the view that referees are deliberately biased. Some of them are pretty ordinary (good morning, Mr Mason), but I don't believe any are dishonest.