If you own a Gally only play with other Gally owners. That way all the people who wanted the nerf but at the same time always want your help can't get it.
Edit 1: In my experiences most of the people starting groups saying you must have a ghorn are looking for help not elitist. It's people who can't play the game asking for the help of the almighty rocket launcher that have caused the problem so let them do it on their own.
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I agree with this. Require it for everything. Even crucible. That will teach bungie a lesson. No gjallarhorn? Instant kick.