They explain this by the fact that due to the fact that they duplicated the transaction, which was carried out by me at the beginning of 2020, I must return this amount now.
Do they even know how crypto works there at Binance?
And the fact that they mistakenly sent to this address is the basis for binance to consider this address as mine, regardless of whether I have access to it or not.
That's BS! Binance (as far as I know) doesn't require users to withdraw only to their own addresses. That would for instance make it impossible to transfer funds directly to another exchange. It's quite common practice for users to make a payment directly from an exchange. And on top of that, even if you owned the address, Binance doesn't require you to keep having access to the address you used 19 months ago.
Binance is acting like a bank here, and in this case you told your bank to pay a certain amount. If they repeat that same payment 19 months later, they can't hold you liable for it. What they should do is a big walk of shame for their own mistakes, and man up! They charge users 10 to 100 times more to withdraw than they pay on-chain, so it feels like karma if they now pay the price for being cheap on transaction fees.
They're now just trying to grab funds from customers to limit their own losses. I assume they'll get lawsuits over this.