"Just get new friends" is definitely callow, but muting someone for a while on Facebook isn't the same as shutting them out of your whole life forever.
Maybe I've misunderstood what the implication was supposed to be-in lived experience when told "just get new friends" that suggestion very often stopped short of offering anything further like "use the snooze function" (which I'm already doing quite a bit) or other recommendations to better 'curate' the feed.
It very rarely feels like a recommendation to improve the experience and a call to action, instead to sever personal connections.