This sounds like some sort of novel logical error, sort of like attacking the man rather than the argument but instead the idea seems to be:

arguments that emit from sources you would expect to be making such arguments are automatically discounted.

This leads to the conclusion that only arguments from unexpected sources are to be trusted - thus criminals who argue that crime is bad and snitches should get riches are to be trusted, but cops who say that crime is bad are not to be trusted on that matter.

I mean, it's a funny kind of idea to hold.