The Wolves seem to be kind of cult-like. But most cults want to increase their numbers. The Wolves just seem to want to kill people. Not sure what they want.
There are more besides the ones who got into Alexandria, right?
They may see themselves like the cult of Kali - their job is killing everyone who isn’t them.
And in a world with dwindling supplies for the living, they may not be interested in converts - just killing competition simply to keep their own numbers stable, fed and sheltered.