There is plenty of feedback around the latest upgrade, which seemed to remove a lot of functionality that used to exist.  Safe to say it’s awful.  But, I won’t even harp on that any more.  However, the fact that it was released is a travesty.  I think that the best way to show unhappiness is to let the Apple (or Google) Store know that the app is terrible.  Perhaps influencing the Sonos rating there may have more of a hope of preventing this sort of nonsense moving forward.  Having existing users complain to Sonos directly seems to not really help, perhaps complaining in a forum where people might look if they want to users will change the culture that allowed this to happen.

P.S.  Seriously Sonos, give the user the ability to also remove Sonos Radio.  Forcing that is just a constant annoyance as well.