Technically, there’s probably no such thing as a frivolous grievance. This process is set up under the terms of a collective bargaining agreement, not a court of law. And who cares if lawyers get rich on this? You and I aren’t paying them. Colin Kaepernick and the NFL are.
Of course there are frivolous grievances, and this is a perfect example. As I’ve noted at other times, you are absolutely entitled to your point of view. But so are others entitled to theirs, and mine is unshakable that whatever it’s called and through whatever means it’s being brought, this is a frivolous claim.