There’s a lot of unintentional ignorance out there, so let’s get something straight.
If you’re a woman, and you call him Cindy Crosby, or you call them the Sedin Sisters, or you think “Two Girls No Cup” is funny, do you know what you’re doing? You are calling someone female to insult them. You are using yourself as an insult. Have a little more respect for yourself.
If you’re a man, and you make Cindy/Sedin Sisters jokes at me to make me laugh, do you know what you are doing? You are using me as an insult. Why would I find that funny? In fact, making a joke like that at me pretty much guarantees I won’t want to have anything more to do with you.
Maybe you don’t mean to be sexist. Maybe you make that joke because everybody makes jokes like that, and have been doing that for a long, long time. Even women laugh at those jokes, and wear those shirts. What’s the big deal? The big deal is that nobody makes a big deal out of it.
So let’s start. When someone makes a joke like that, politely break the joke down for them. In the last day alone I’ve pointed it out to three people and received a favourable response. “You’re right. I’m sorry.” No need to yell, belittle, or make someone feel like they murdered a puppy. Just break it down nicely. If someone doesn’t get it, then yes, they have serious problems, but trying to educate people without attacking them seems to work pretty well on this particular issue.
Oh, and if you are anyone and you own a Two Girls No Cup shirt, burn it. Don’t give it to charity. Burn it. Don’t cut it up and turn it into rags you can clean your car with. Burn it.