You do realize that these protests aren't about Police treatment anymore and haven't been for awhile. It's something that started that way and morphed into a tool they are using for anything they don't like with the league right now. Which is why I stated I wish they would do something drastic to force some sort of change so they could stop using it in that fashion. It's to the point now that any hot topic that comes up in the league the response is we don't like that and if you don't change it we will kneel. And unlike all the other leagues the NFL players have yet to realize that they do have all of the power and can force not only work condition changes in the league but get the league to address issues they feel are important (at least in the best of their ability). But sadly I think it's past that point now strickluy because of the Kapernick issue. The continue to have that on the top of their list of issues attempting to force a team to give him a starting job. Even if someone caved and gave him a shot it would just become another level of issues from he wasn't given a fair chance to they need to change stuff to suit how he plays. And maybe
@Ledboots and
@Duke is right in the comments that they act differently because their careers are shorter and there's a much higher documented rate of them being broke shortly after they stop playing.
So to answer your question they are wanting and are damaging the league. At least in its current state. They would prefer to purge all of the rules and most of the owners in the current state and have a league paying them what they want but in a more utopian model. This view is no different than views that have been part of 100s of union represented jobs. From auto, steel, airline, etc. And the way those have made changes is by striking and walking out.