So, are you saying teams shouldn't even kick the tires? A GM's job is to make the team better. Why wouldn't after an injury or identifying a QB weakness in training camp at least fly him in for a tryout?
Kaep is 32 years old. That's no spring chicken, but going into the start of this season it's younger than 10 of the season starting QBs (Brady, Fitz, Ben, Dalton, Rivers, Flacco, Eli, Rodgers, Brees & Ryan).
If the GM of a team who needed a QB was a doctor not bringing in Kaep would be cause for a malpractice lawsuit. It's like your patient saying their chest feels tight and have pain in their shoulders/neck and your refuse to send him to the ER to see a cardiologist. He's getting black balled, period. I'm not debating if he 'deserves' to be black balled or not, because that branches into your thoughts on racial tensions, patriotism and just rules in general, which I have no interest in discussing.
Teams are going out of their way not to give him a chance to work.