The issue you are addressing happens only (?) in a few maps that have trigger_hurt and I know a few players who tend to do it more or less often. Sometimes other players join the party when they see someone doing it but other than that this issue is not really global (in all maps). So I don't see a point to add any restrictions that will just make the gameplay worse for 99.999% of players just because of what you can do in a few maps. Admins can just simply kick/forcespec those players who disrupt the game in this way.
Please be more concretic and properly point out the issue when making a report. That one screenshot doesn't prove that the message was meant for you. Are you upset that you were punished while someone else wasn't? Admins can't always see everything that is going on in the chat/game. I wouldn't think that there is a big unjust conspirary revolving around you based on one occurance.