I was in 3 different long lasting D&D groups in the 1980s. I think most of us would have loved to have girls join, but no girls played with us in that decade. Whenever we got the balls to ask a girl to play they just looked at us like we were crazy, like they would get nerd cooties. I went to a D&D convention in New Haven at that time and I remember there was only one girl out of about 500 guys. She was very popular, with a whole lot of guys wanting to be in her group.
There certainly was a social penalty for me being a nerd at that time, but I didn't feel I had a choice. I loved gaming and it was part of my identity. At that time, however, I think there was a larger penalty for female nerds coming from the non-gaming community than for male nerds. Any girl joining our very small and admittedly not very attractive group probably would have been marked as a pariah by mainstream social groups.
DM: "You walk into an underground chamber. At the other end of the chamber is a large chest with a lock. On either side of the chest is a marble pillar carved into the shape of a woman. The woman on the left has a sword and the woman on the right has a battle ax."
Thief: "I take out my lock-pick and walk to the--"
Magic-User: "Don't move! Those statues are going to come to life!"
Thief: "What makes you think that? That sounds quite unlikely to me."
Magic-User: "You're new around here, aren't you?"
It's reasonable to expect all people to refrain from credibly threatening the lives of others.
Sorry, but it really is unreasonable to expect ALL people from credibly threatening the lives of others. After all, these are people we are talking about. Maybe you don't have a lot of experience with people, but some are really messed up. Since we are talking about credible threats, it's reasonable for us to kill anyone who makes these credible threats.
As a disclaimer I'll point out that the above threat is not credible.