The NHL is an entertainment league. Colin Kaepernick did nothing discriminatory, doesn't mean he wasn't pretty quickly dismissed from professional play for his beliefs.
So he should sue if he was also treated unfairly. The difference here is he did something voluntarily while the hockey players were effectively being forced to do something "voluntarily".
BTW, I don't see Kaepernick as being some sort of leader and can easily see where he was leveraging being a "social justice warrior" for personal gain. I get zero sense that he was doing anything useful about the cause he was supporting (a cause that is dwarfed by black men killing each other or doing activities that brings them into engaging with police in the first place) so do not have much respect for his action on the field.
After hearing him denounce his parents, he comes across as not an overly bright individual but more of a "useful idiot".
I have the same sense about the players who choose not to wear the jerseys. They aren't doing anything that comes across as intellectually special; they are followers.
You have the right to practice your beliefs, there can still be repercussions in an entertainment industry. Teams don't want to field negative PR or lose fans because X, Y, or Z and this could be any of those letters. There are other more severe red flags, like how it's pretty unlikely any of that Canadian 5 will see NHL contracts for quite some time, but this is also totally allowed to be one. Tony DeAngelo has had a weird time getting work, it's not illegal to not want PR headaches.
The NHL has a choice as to what PR they want. Allowing those to do what they want while not forcing things on players is the right way, IMO.
Willingly getting caught up in the culture war is not a good idea as you are always going to be potentially pushing away those on the "wrong side" while trying to be on the "right side".
A review of practices and promotions to ensure there is nothing glaringly non-inclusive, which I am sure is the case, is fine.
Here's the real thing though: does this mean you also disagree with the "Hockey is for Everyone" initiative? One can very easily argue that wearing these jerseys is demonstrative of the idea that anyone can and should be welcomed to play or otherwise enjoy the sport. They're not "Gay Marriage" jerseys where the nameplate says "Support Proposition:" and the number is whatever recent thing in the area, it's not really "political" beyond a one night demonstration that those groups are "welcome" (even though we're having this conversation right now which suggests that's less true than it should be).
This is only political if those are your politics.
Placing
everyone into an identity box based on race, gender, religion, sex, etc... is identity politics.
Presuming that people who faced historical discrimination need to feel "welcome" because society doesn't like them is, IMO, infantilizing and condescending. It is something I certainly would not tell any young person.
I support a colour, gender, sex, etc - blind society.
