Punishing people for endorsing comments that don't meet an arbitrary and vague content standard will inhibit endorsements.
This happens already with flagging and downvoting. If you flag or downvote too often/aggressively/whatever, you will have those privileges revoked. I used to go to /newest daily and upvote/flag until I lost my flagging privileges. I eventually got the ability to flag back but now I rarely go to /newest. It's the tragedy of the commons - if I go to /newest and flag/upvote, this is a better community because I'm active and participating. But if I am worried about being punished from doing so, I won't do it and will just hope that others will.
This happens already with flagging and downvoting. If you flag or downvote too often/aggressively/whatever, you will have those privileges revoked. I used to go to /newest daily and upvote/flag until I lost my flagging privileges. I eventually got the ability to flag back but now I rarely go to /newest. It's the tragedy of the commons - if I go to /newest and flag/upvote, this is a better community because I'm active and participating. But if I am worried about being punished from doing so, I won't do it and will just hope that others will.