Sure, the mother might be trying to do what's best for their sons, and maybe small smothering is not such a huge problem, but when they do it TOO much, little by little, the son may start to hate her and just want to move out as soon as possible and never want to have any kind of contact with her ever again.
This is a reccurring question. I wonder why it continues to be posted.
Someone could be seeking some sort of validation, perhaps? Projecting a bit of personal struggle? Maybe someone was made fun of for being a "moma's" boy, and wants to set the record straight?
Who knows, but one thing is for sure. The person most interested in this question might have some Oedipal things to work out.