Story mode co-op level 90 players joining

Why is there no way to prevent level 90 players from joining the story mode if you have a public lobby maybe players want to play with other players in the story but don't want some level 90 pos relentlessly joining following them when slaughtering the boss every time genuinely and if you answer is down scaling you are an idiot these people are effectively griefing me into playing by myself and It quite literally happens every single time you make a public lobby for the story it's unavoidable. I'm not sure how a level restriction option hasn't been implemented but if it stays like this I definitely won't continue to play you literally can't enjoy the story unless you play solo by yourself or with people that you already know so if you're looking to play with new players you're pretty much going to get griefed every time and I'm not going to stick around for that

I literally just had someone join and finish the final boss of the story for me in seconds yeah I'm done with your game this is trash trash ideas

I'll come back if you ever give an option to where I can play public multiplayer without having level 90 and 80 characters come in and just obliterate everything against my will but you have no idea I just spent the entirety of a day beating the whole story to have some POS come in and kill the final boss on me in seconds nothing I could do it's like this is trash it's actual trash whoever thought that was an okay idea to allow people to come in like that and to give no buffer no way to stop them besides you're failed weak azz level down scaling literally my whole experience was just ruined