I'm involved in a charity that also ends up with a good amount of computer donations. Unfortunately, we have to be ruthless with what we accept. We have to pay to dispose of ewaste.
In practice, laptops with a dual core processor or higher can be put to use or given a new home. Anything older is useless. We still need to sort through and thin out the numbers at that level however.
Unless you're willing to store the computers for them, until a unicorn comes in asking for one, it's likely a practicality issue. While it's far from perfect, it's required to keep shops like that functioning at all.
A better option might be to go to a retro gaming shop/cafe. They are more likely to stock old hardware to play older games natively. It's mostly consoles, but some also have PCs.