It's got to be stopped, and it will only get worse the more it grows.
I've been keeping an eye on the meter at https://instances.social/mastodon.social and it currently shows mastodon.social as 13.8% of all Fedi users.
I know it will be painful for people to defederate from 1 in 7 users, but it will be a lot less painful than 1 in 4, or 1 in 2, or wherever it is heading for on the current course.