How come TF2 models can't touch their bodies?

For example, take the Heavy’s model from TF2. You can’t put his hand directly on his face. Why is that and is there a way around that?

Theres a .phy fix somewhere for that

Because they don’t believe in masturbation.

This.

Also for some reason they are REALLY “heavy” on the phys gun! Like I can BEARLY lift em up!

The Heavy’s minigun is heavy as hell, you can’t weld it to a hand and have it stay because it just drops like a rock.