"Best programmers" and "people who contribute effectively to a team's culture" can sometimes be exclusive sets.
One of the most intelligent and creative programmers I know is an arrogant douchebag who demoralises entire teams. He's very effective on his own, but stick him in a scrum team, and watch the culture of that team sour and watch its productivity drop.
And if your team culture is "let's be interesting creative people with zany hairstyles and really unusual hobbies" (not my team, but I sit beside them), then someone who is passionate mainly about checked exceptions is probably going to be a bad fit.
I used the arrogant douchebag as an example of why a great programmer who doesn't fit a team's culture is going to drag down the productivity of that team - how they don't fit that culture can obviously vary.
The team I work on has gone from a culture of "single guys who stay after work playing board games and go out drinking sometimes" to a culture of "married guys who leave promptly at 5 PM to go home to their pregnant wives and/or children" by gradually introducing people from the second set while people from the first set leave. Guess what? It didn't affect how much we managed to accomplish, because it's work and that bullshit doesn't really matter.
One of the most intelligent and creative programmers I know is an arrogant douchebag who demoralises entire teams. He's very effective on his own, but stick him in a scrum team, and watch the culture of that team sour and watch its productivity drop.