It's the same bullshit argument used by Spotify and Klarna. If the companies are already providing better terms then there's even less reason to not sign a collective bargaining agreement: the CBA only sets the lower bar, anything over that the companies are free to provide as they do right now. Nothing changes if that's the argument.

What they are trying to hide is the argument that a CBA will give power to employees during major reorgs with layoffs, a CBA doesn't set an upper bound to what employers can offer as benefits, just a lower one.