I have a proposal regarding this.

If SE absolutely refuses to add performance report cards of any form in a game that has DPS/performance checks in a bid to prevent “toxicity” (though the ones being toxic here are the bad players sneaking into high-end content PFs that they are severely unqualified for)...

Then for high-end content ONLY, they should add a new vote kick reason: “Underperformance.”

With this new vote kick option, if you get a bad/unqualified player sneaking into your clear/farm PFs (“traps,” as the raiding community calls them, for they trap the raid into endless wipes), and they get vote kicked with the new “underperformance” option, they will see the following system message on their screen:

“You have been dismissed from the party for underperforming in the selected high-end content.”

If the toxic casuals want to keep clowning on the players who actually put the effort to learn difficult content, then the latter should also be given a way to “clown” the toxic casuals back in a polite manner that still drives in the point that they don’t currently belong in the PF they’re sneaking into, and I think this revision to the vote kick system should do it.