No one is doing that. Simply stating that putting a requirement of 940+ on a dungeon run that at minimum requires ~900-920 is ridiculous and the reasoning behind it is selfish because YOU want the run to go faster and have no desire to even chance it going slower than you want.
It's not an unreasonable thing to want to be efficient, it's the mentality behind the decision to exclude everyone below 940 under the completely false pretense that you're going to exclude the lazy bad people that is simply ridiculous.
You're group, your rules, that's fair...unreasonable, IMO, but fair.