Chinese captchas can be much worse when you're on domestic websites, to the point where I need to get my wife to solve it for me because I'm not sure which character doesn't have a specific stroke

I believe Binance has the same thing. This to measure my human imperfect way of sliding the puzzle piece, I suppose.

I don't get this captcha tbh. Shouldn't it be trivial to create minor variations based off of a real human slide?

But I don't understand how we can't make a program that has a bit of randomness.

Sure you can, but it's not trivial to make the random seem like a human random at a large scale. What are the parameters of a human slide and what kind of distributions are they? And there might be things they do under the hood that affect those parameters like fingerprinting. You would need a lot of data to imitate a human, but the provider of the captcha has a lot more data than you to counter your effort.

Thats why it's usually just easier to pay some people pennies to solve them by hand.

Ah, interesting, I didn't think of the information asymmetry there, thank you.