Good question. About your “friend.” And your “friendship.” Yikes!
Next time you’re chatting online, don’t let this go by!
If you actually want to move someone’s opinion (the little bit it’s really possible to do that), don’t actually tell him immediately his opinions are racist, sexist, etc. That’ll just make him defensive; people tend to retrench when attacked.
Just to be clear — you have every right to tell him his opinions are racist, sexist, transphobic, etc. But that is not likely to change his mind. Which you have a chance of doing, since you already have a relationship with this person. You could possibly change him for the better so that, for example, the next non-cishet person who crosses his path doesn’t end up having a shittier day because of it.
So, instead of calling him out explicitly, you could try “Whoa, dude! Not cool.” Or, “Holy crap, WTF?” Or, “Okay, Mr. 1955. Maybe keep that one to yourself.”And, “Uh, yikes. Control yourself over there!”
This gives the person a chance to reply, “j/k” or “haha sorry, I forgot you’re my feminazi godless liberal friend haha,” which allows him to save face and — later — it is possible that THE MAGIC HAPPENS, where he actually adjusts his opinion a little bit.
But people do NOT like to adjust their opinion publicly, or apologize, or acknowledge their biases. So to get them to do it, you want to be gentle enough that they can change their opinion privately, later, and then pretend that’s always been their opinion and it has nothing to do with you.
Not that you have an OBLIGATION to do these things. And certainly, people who are members of the groups this guy is disparaging have no obligation to engage or correct this guy or anyone like him. It’s his own job to educate himself.
But you say you’re his friend, so there you go.
Also, this is assuming that you two are having a private conversation. If you were having a public conversation, I think your obligation to the world at large is greater than your obligation to your “friend.” Meaning that you should do anything you can to keep people he might be “sexist, cissexist and homophobic” to from having to hear a single word out of his awful fucking mouth.
Since you let the chat go by without saying anything this time, send him a very short message that says something like, “Hey, last time we talked you said some things I found pretty troubling. Just so you know, I obviously think men and women can do the same parenting jobs (and regular jobs), and I support LGBT people and people of all gender expressions.”
He might just ignore it or reply “Sorry lol” (and change his opinion a little bit without mentioning it to you). Or he might want to talk about it. Or he might say something awful and then you defriend him.
Note that “your comments are troubling” is non-gendered, whereas “I’m upset” and “I’m offended” are gendered, and may prompt a misogynist to try to put the problem back on you.
Don’t write long messages trying to persuade him (I’m a fan of, “I’ve gotta run, but here’s a helpful link”).
Keep your tone unemotional and treat him like a kindergartener flinging shit on the schoolroom walls; you don’t really have time to explain why that’s NOT A THING WE DO.
Give him a chance to pretend he was joking and change his tune. If that doesn’t work, defriend him. Your views and rejection of him may still cause him to, someday, in some small way, change his point of view. (How many old white people do you know who pretend they were never racist, when you totally remember the shit they said when you were a kid? Now society has changed and they’re embarrassed, and they’ve gotten with the program at least a little.)
On the one hand, it’s shitty that this is how humans are.
On the other hand, I think you can maintain some hope that you’ve done some good in the world when you argue, share articles, try to educate, etc., even if if it seems futile. Sometimes it takes awhile.
And sometimes you just need to block someone.