Beau of the Fifth Column has a great way of dealing with this sort of bigoted joke actually, "Huh? I don't get it. What's funny about that? What's the joke?"
And just like... watch them realise they can't explain it without sounding like a monster.
And to anyone who would say that jokes are like frogs, you can't dissect them without killing them: you've never seen a good comedian break down a joke. It is hilarious, it's all in the telling. If you need to rely on shock to get your laughs then you're not actually funny. You fell into the shock-jock trap of "oh that got a reaction; that must be funny", not realising that people also laugh when they're uncomfortable, and all you're doing is being an asshole.
Has it occurred to you that pressing the downvote button is just much easier that having to bother explaining something that should be obvious?
If it is not obvious to you that it's not incel shit, maybe even after an explanation you won't agree still because you have different views (which I'm not saying are not respectable, but are still different, so an agreement can't be reached), so whoever replies to you would have wasted their time.
Two people go on a date. The date is going well, there is chemistry between the two people. One says "if you beat me at any game we can have sex". The two people will typically play a board or card game, and will flirt with the opportunity of sex during the game play, which is gonna be fun and exciting. Seems a good plot idea for your average romantic comedy movie or teenager's series.
Now the joke is that the choice of game is stupid because you end up killing your date. Just with that you could make a meme/joke. Now the post is doubling down on the stupidity, insanity, etc., by making it morbid and showing that the guy still had sex with the corpse.
Here it is. My take on the issue, which is unlikely to be the only possible explanation which is not "incel shit". I've wasted 10 minutes of my time, and you'll likely will still not agree with me, and will prove valid my first comment.