How about the win loss record of Mark Rypien, or Mark “Butt Fumble” Sanchez, or Rex Grossman, or any number of the dozens of QBs who got chances Kaep didn’t get. You can argue about his actions all you want, but don’t pretend he’s not playing for football reasons.
No one is arguing he should replace Brady or Mahomes. With at least two QBs on every roster, there are 60+ jobs available, and he’s certainly better than at least 20-30 of those on rosters.
Backups are of two types: young guys who are unproven and veterans whose records aren’t good enough to be the starter. Kaep is at least good enough to be in the latter category. He started a Super Bowl and he actually played decently in that last year. The team was awful.
You have to look at the total picture and determine how much of the lousy record is on the quarterback and how much is on other factors. As an analogy, take two baseball pitchers with equal losing records. The first one has a very low ERA and more strike-outs than walks but plays on a lousy team with no run-support. The second has a very high ERA and more walks than strike-outs. You would not equate both of them.
Back to Kaepernick, the standard trajectory for a quarterback with his performance record would have been that some team would have signed him as a back-up quarterback, possibly with visions of resurrecting his career as a starter. Then, most likely, he would not have progressed further but would have hung around the league as a second or third-string quarterback before eventually not being signed by a team and then fading away.
Edit: As a real-life example, in the early 1990s the then-Los Angeles Raiders were quarterbacked by Jay Schroeder. Schroeder was a head-case who tended to make bone-headed mistakes, but the Raiders had a winning record. I remember once having a discussion over the subject with a guy who felt Schroeder was doing well. He asked me if Schroeder was so lousy then why did the Raiders have a winning record. I replied that the Raiders had a winning record in spite of Schroeder, not because of him. The person acknowledged that I might have had a point.
From a long term/strategic perspective (which government-funded organizations never seem to want to consider), you can’t treat prisoners like human waste, or they will just return to their old ways when paroled or released. Prisons that do that are basically just creating more future criminals.
Same reason you can’t brand them with a permanent record over one offense. If they can’t get a job & have a normal life & dignity, there’s no reason to expect them to follow laws & respect others.