This is my attempt at a substantive reply to the original post. There are two distinct issues involved here. They are :
1. Is the player good enough to play and be worth signing?; and,
2. How important are the side issues, and do they affect your view of whether you want him on your team?
In addressing the first issue, I think many people make the mistake of assuming that winning is attributable to that player. That is partially true, because if a player plays in the game he contributes to wins and losses in some way. But a win doesn't equate to Kaepernick is good and a loss doesn't necessarily mean he is bad. You have to view his play in its own right to properly evaluate him.
Kaepernick played well enough to get to the super bowl in his early playing days. So one might draw the conclusion that he is "good enough" since he led his team to the super bowl. Although that would be a reasonable conclusion to draw I do not believe it is the correct conclusion based on the facts.
Kaep had a very good surrounding cast, which is why the team made it to the super bowl. They also had very good coaching
I believe Kaep's problem is that eventually teams figure out what you can do and can't do well. Once teams figured out that if you force him to beat you with his arm he just can't do it. His mobility was his biggest weapon, and they shut that down. I believe Kaep's days in the NFL are likely done based on his limited skill set. As a side note I am somewhat concerned that Dak "could" run into a similar issue, but to a lesser extent as teams figure out his limitations.
Regarding the second issue, I personally feel like Kaep is entitled to his own opinion. I am all for freedom of speech and having one's own ideas. In this case, Kaep's opinion can directly hurt his employer. It can cost his employer money.
Kaep made a point to make an issue of it politically, while on the job. I believe it is reasonable that teams would not want to buy into that unless he were a superior talent. It does not appear that he is a superior talent. I really think Kaep saw the axe coming his way and decided peer pressure might save his job. It ultimately didn't.
As a side note, Kaep could have said, hey, I'm not into this flag saluting thing, I don't want to be forced to do it, how about I come out after it is over and we can keep it on the down low. If the media asked about it he could have said he doesn't come out until later because he gets treatment right until kickoff.
When you are the point man and it affects your employer adversely, and you don't give them a graceful way out of it, then you create your own problems.
Kaep doesn't have a job because he is not very good. Whatever his chances are that a team would take a risk on him based on his ability go down that much more because he brings unpopular press upon his team. It is really that simple.