Because,,, from Shane's POV: you LOVED being captain. Specifically, you loved being Montreal's captain. You were respected and revered and you had a place on your team, a strictly defined role, and we all know how much you love strict rules. In the hieracichal system of hockey, you were at the top and goddammit you EARNED that place at the top - it is irrefutable evidence of your work and talent. And now, you've just had to leave your beloved team essentially in disgrace and you have to join a new team where you're not sure where you fit, but it's not going to be at the top. And no matter how much you love the man who's now calling the shots, it's gotta sting to be demoted like that.

As for Ilya's POV: Being captain of the Centaurs was the one thing that gave you even the shakiest sense of purpose in the malaise of change and newness of leaving behind everything you knew in Boston. And goddammit you feel a righteous sense of ownership over this team that's finally excelling, becoming a real franchise competitor, and yes there were a lot of contributing factors but one of those contributions was YOU. You love being captain, getting to control your room. And it does feel like YOUR room now. That sense of belonging, that's not something you're willing to give up, it's something you worked for. And, in a smaller, prettier way, haven't you given up enough by now? You deserve to keep this.

LIKE ‼️‼️ THAT'S FASCINATING!!!! And don't get me STARTED on how this friction in the locker room is probably gonna trickle down in some capacity to hollanovs sex life,,, Shane's genuine desire to submit to Ilya sexually is gonna have a tough time rubbing up against Shane's internalised homophobia,,, because when Shane was captain of the metros, him and Ilya were equals and competitors,,, their even footing soothed Shane's perception of himself and his sense of masculinity,,, now that he's Ilya's 'subordinate' in their work life too, I think there's gonna be an instinctive defensive posturing flare up on Shane's side that's probably gonna lead to even MORE friction in the locker room because subconsciously, Shane feels like he has to make up for the sin of submitting to and enjoying Ilya's control over their sex life, and that's gonna manifest as him bucking control in their professional lives

As for Ilya, his already ingrained need for control that makes him such an adept dom is really gonna struggle in the face of Shane's strange sudden defiance in their professional lives, which is probably gonna make him instinctively tighten his grip on the reins, which is just gonna make Shane's bridling worse. And the cycle will continue until they have a blow up fight about it.