Another from Nyah Wynne to get things started.
Somehow we have gotten this notion in the culture that humor is value-neutral. That something being a joke means it doesn't mean anything, it doesn't affect anything. But it's absurd. Humor has a powerful social function. Several in fact. It can help people bind over shared adversity. It can smooth over feelings of social discomfort around uncomfortable or uncertain events and ideas. In this last, a message about how to think about something is often included implicitly. But it also plays a very large role in social censure and definition of in/out group. As social censure it acts as an attack against people -doing- things that are culturally deemed unacceptable but not so bad that they warrant punishment(or where social systems don't exist to enact punishment). This can be very useful, as mocking those acting rudely or engaging in petty cruelty can help to correct those actions, or can be destructive if the taboos they enforce/reinforce are unjust.But this same social censure can end up targeting whole groups of people along utterly arbitrary lines. And when they do they tend to create/reinforce and recreate in each new generation systems of social advantage/oppression. Humor is possibly The Strongest Inculcation Tool for teaching prejudice. Because it is a set of social cues we are primed to respond to without thinking. Because humor has such a strong group-bonding component, the social incentive to laugh along with the joke is high. And when you see others laugh with the joke, the incentive to tell similar jokes is high. And the group bonds over it, and the message sinks in without really ever being critically appraised. And eventually that message forms a baseline subconscious assumption about the world unless you run into a strong reason to actively work to weed it out.It ends up defining on a deep level who is and isn't fully worthy of empathy. Who 'deserves' abuse. Who should automatically be respected and who shouldn't. And these same things end up coloring how we see the world. How we respond to what people in various groups say and how they act. Who is given the benefit of the doubt and who is suspect.Because the same mechanism involved in many of these sorts of jokes is the social tool we use to single out rude people, or liars, or people who cheat. It's never just a joke. It's a bit of prejudice you learned at some point that you never even noticed yourself learning, which you are passing on without realizing you are doing it.And the people it targets aren't likely to find it very funny.
In general a useful analysis of joking.
The in-group bonding function of humor is its most important function. Jokes about the out-group reinforce the behaviors that are unacceptable for the in-group.