It appears these bikes were designed to not be user serviceable. Bespoke tools are needed to do any maintenance and there aren't off the shelf parts for anyone who would need anything replaced. This seems very different than selling a used car where the new owner would still have some expectation of being able to service and repair it. Presumably they also have bespoke chargers and not enough to sell with every bike so some people would be buying e-bikes that can't ever be charged.

That's not an argument for not making them available. But it does substantially decrease the value. It's possible it pushes the value below what they'd get from recycling. If that's the case, it's easy to see why they'd recycle them instead of spending more time/money to try to sell a non-servicable and non-chargeable used bike.