Filmmaker Spike Lee is supporting* a “United We Stand for Colin Kaepernick” rally outside the offices of the National Football League in New York City on August 23.

Of course, it’s not the league that is preventing the former San Francisco 49ers quarterback from signing with another team; Kaepernick isn’t suspended or facing any discipline from Commissioner Roger Goodell. A variety of factors are preventing Kaepernick from suiting up for another team this year.

Begin with the obvious, that probably half to two-thirds of the teams in the NFL feel set at quarterback right now. Then there’s the issue of Kaepernick’s skills as a player. On paper, he had a good season last year, with 16 touchdowns and four interceptions, but he began the year as a backup to Blaine Gabbert and only played after Gabbert struggled in the first five weeks. Kaepernick had some good games and some bad games, but San Francisco, one of the worst teams in the league, was comfortable letting him go and moving on. Quite a few teams seem to think Kaepernick’s best years are behind him.

But the controversies that surround Kaepernick off the field are the real reason others are willing to rally for him. In his final season with San Francisco, Kaepnerick refused to stand for the national anthem, wore socks that portrayed police as pigs, wore a t-shirt that depicted Fidel Castro — while denouncing police brutality! — and so on. In March, Kaepernick said he would not continue his protest this season, but he’s undoubtedly a controversy magnet.

Is it really hard to imagine why a football franchise in Miami would be wary about signing a quarterback who praised Fidel Castro?

Many in sports media are arguing about how to interpret J.D. Power and Associates poll that found 26 percent of those who watched fewer games last season said that national anthem protests, some of which were led by Kaepernick, were the reason. It’s worth noting that only 12 percent of the surveyed fans said they watched fewer NFL games last season, and 27 percent said they watched more. But overall, broadcasters saw an 8 percent drop in viewers.

Last Friday I asked Kaepernick critics on Twitter and Facebook just what the appropriate response to his controversial remarks and views are. Is booing him sufficient, or are NFL fans who don’t like his stances comfortable with him never playing football again over them? (This question is particularly interesting in light of the outrage over the fired Google engineer. How comfortable are we about someone being denied an opportunity for employment over political views?)

At least on social media, most Kaepernick critics indicated they were perfectly comfortable with Kaepernick never playing in the NFL again.

* This initially said “organizing”; in a subsequent Tweet, Lee said he is not organizing the event but he supports it.