I don't look at the national anthem as being synonymous with the military, thus I don't consider his dissing of the national anthem a dissing of the military per se.  Although there's certainly a lot of indirect overlap with the national anthem, patriotism, the flag, and the military.  Including our regular inclusion of the military in such ceremonies.  So I can see how some might extend it to that.

But I don't extend it that far.  Kaepernick flat-out disrespected the national anthem, over and over. And spawned a handful of others that did the same.  Whether their cause was worthy or not is irrelevant, IMO.  There's ample opportunities for NFL stars to leverage their fame and their built-in media coverage to protest a cause if they want, WITHOUT dissing the national anthem and all that it stands for.  He made a terrible choice, and he's paying the price for it.  And rightfully so, IMO.