As a mere mortal, simply speaking out of my emotional reaction to prideful, nasty, selfish people, my temptation is to say, “Good riddance.”
However, one of the things being Catholic *forces* you to do (if you want to be an actual disciple and not just a yakker) is to think with the mind of the Church. And the mind of the Church is, very obviously, “These are people for whom Christ died.” So their departure is a tragedy and I pray they will return and not continue this schism.