Guns are a large part of our household. My kids are being raised knowing how dangerous the decisions we make with guns can be. Not that the gun is the enemy. That being said, my four year old son won't point his finger or a toy at anyone with the intent of imitating a gunshot.
We live in a rural setting, and like I said; guns are a large part of our household. We reload, hunt and shoot. A lot. You could have asked either of our kids back when they were three "what are we allowed to shoot?" And the reply would have been something to the extent of "Bunnies, squirrels, coyotes and deer. And only you can shoot grandpas cow." (Yes, my grandfather has a beef farm, and we do our own butchering. ...And I had to explain that process... Aaahhh fatherhood...)
I've played Halo in front of my kids, and explained to them that it is a game - just that. It also helps that Halo doesn't look as real as most games though and we don't play the others for that reason. Some of their favorite cartoons were: woody woodpecker, Tom and Jerry and most of the other older ones. Violent ones alike.
If a kid pointed a finger at someone and went "bang" around here, little would probably happen. But then again, they don't know what a gang is either. Everything is relative.
Perhaps the youngster who was suspended has done this a hundred times in the past, and was told that its not acceptable behavior. Maybe it was story time, and the kid should have been paying attention for the hundredth time. Maybe the school is located in a poverty and gang stricken community where the threat of someone shooting someone is near. Maybe the rules were already stated, and it wasn't the finger that got his but suspended - but his disregard for obedience or the teacher.
I bet you we all can think of a time where when we were in our childhood we received discipline that was far more severe than the kids nowadays do for the same infraction. For example: I, just twenty years ago flipped the bird to a kid. The teacher told me that if I did it again that my parents would have to come in to get my finger off of her desk. I sat not near enough to her desk that my arm would have reached. I'm sure she wouldn't have actually chopped my finger off! Lol, but I also know that I wasn't going to test her either. Now, if a student does that it's (IMHO) a slap on the wrist. They know that the teachers can't do anything, so they do whatever they want.
All I am trying to say is; perhaps we don't know every part of the situation here. I certainly don't know the history of the youngster or the teacher in question.
Indeed times have changed. IMHO not always for the better. Trying to understand both sides of the story seems to help a lot though.