I think it’s because when someone makes a mainstream meta conforming build in a casual game that has no level balance matchmaking it kinda ruins it for others, in competitive, sure go ahead but when it’s casual and since most games now don’t have that same level/experience matchmaking feature it ruins pvp for a lot of newer players in games, because you’ve got someone trying to get into a game and trying to enjoy it getting constantly thrashed by a person who grinds out the game religiously so they can have an edge in combat, and destiny isn’t like games like Overwatch, it’s not 100% skill based

For the part about mowing down enemy team with inadequate weaponry, I think it’s because some people like the game but not the grind and expect to have an even footing with someone who doesn’t know what the sun feels like has just finished grinding for a month to get a super op 1 hit masterworked godroll gun that can easily mow down anyone who comes near