This is a very wrong-headed statement. Most skinheads are white, therefore no whites can be trusted. A complete non-sequitor.
Kind of like most rattle snakes are piousness, therefore no rattle snakes can be trusted.
Actually, the comparative statement would be:
Most poisonous creatures are snakes, so no snakes can be trusted.
The reason you may have thought your comment made sense is because there are cases where it would make sense. If you were going to randomly search a few people, and all terrorists were muslim, you would randomly search only muslims.
But it makes no sense as a statement of action against a people. In fact, it is precisely the textbook example of a racist comment -- saying that no muslim can be trusted because of the actions of a few muslims.
Is this the DU, I could have sworn I typed in Free Republic?