If you think comedy largely has to be offensive and that ribbing your friends is the same as somebody going on TV and saying the same thing, you're missing out on a lot of good comedy. There's so much comedy that doesn't just come down to "saying something offensive for the shock factor."

See it’s based on everyone being equal and there is nothing wrong with being disabled (the person mentioning this view was disabled). So if you rip on all your friends for whatever, but then don’t rip on your disabled friend for being disabled then that is treating them like that can’t handle it or that they aren’t equal.

This comes off like "I can say the N word because I have a black friend and he finds it funny when I say it." Ribbing your friends has the implicit understanding between you and them that it's not ill intentioned or mean-spirited. You could make a joke about your friend's wheelchair, but you wouldn't walk up to a random person on the street in a wheelchair and make fun of them for it. You can make a racist joke with your friends because everybody there knows you're not being serious and you're probably making fun of the people who would actually make a joke like that, but if you go up in front of a bunch of strangers and do the same joke, they don't know that you're not being serious about it. It just sounds like you're being racist.

Punching up and punching down are very specific things, not just joking about a minority group or not; and they're not laws or rules, they're labels for a concept. Calling something a square isn't some self imposed rule - it's just the label for a rectangle that has 4 sides of identical length.

Punching down is specifically when you make jokes at the expense of a minority, rather than making jokes about a minority. It's the comedy equivalent of kicking a kid in the balls because your friends think it's funny. You can make trans jokes without it being yet another "I saw a chick with a dick and that's gross and I vomited" kind of joke. Punching down would be going on TV and making jokes about how black people aren't as intelligent as white people and that's why they're poor and do drugs and end up in prison. Not punching down would be making a joke about how all day people kept coming up to you and telling you how proud of you they are for being brave enough to be yourself and wishing you well in your transition...but you're not trans, you just forgot to put on makeup that day.

Punching up is when a joke is a criticism of a common minority experience at the expense of the people who perpetrate that experience. Like making a joke about how you know that a new black guy moved into town because suddenly everybody is calling you by his name; and when you finally meet the guy, it's like you're already best friends because you already know everything about each other. And then a random black guy you don't recognize shows up drunk in front of your house so you bring him over to your friend's house because you assume he's a friend of theirs - but they had brought him over to your house first because they assumed he was your friend.

Basically, if you have to be an asshole to be funny, then the only people who are gonna laugh are other assholes.