humor and/or mockery while moderating

Whereas today and in the majority of the time one tends to confuse humor and mockery (the limit between the two is more or less thin).
As group mod, we have to keep our rooms safe and supportive, avoiding the conflicts in the room and stop the behaviors that can be hurtful for our members.
In this sense, we ask them to be respectful, to keep our rooms supportive. and eventually we give warning if they continue (the fact it's repeated lead us to think it's harassment or stigmatiztaion).
As a result of it, we get people complaining that we are abusing of our power because they were just "joking", some even threat to make a report.
Is that really bad or abusive to be prudent, when we know that many members are victimes of bullying and harassment on our rooms? To ask them to find more appropriate jokes? I don't feel it's the place for this kind of joke, neither it should be tolerate. But is it ok to continue to give warnings even if it's just "a joke"?
Because here, we can't just look the situation in this globally, and use different strategies with different members in function of the relationship they have with the other participant(s), neither in function of if its punctual or if its something regular on our rooms. We have to act the same with everyone and at all time, we need consistence.

tagging @Amelia @Laura @lovelyllama13 @Jenna