Many reasons, such as
* I have no reason to accept zaps, they don't offer me anything
* Promoting a shitcoin is a bad idea
* Handling refund requests would be a chore because I'm targeted and this is a dangerous era
Discussion
Explain why you think that Bitcoin is a shitcoin.
Why would you be expected to refund anyone?
How does receiving Bitcoin not offer you anything? You can always just send it on to other people if you don't want it.
Lightning is a shitcoin, not Bitcoin
I'd probably have to refund some people to manage anger
I have enough Bitcoin and sending it on to other people isn't helping them, it's promoting lightning