That's all fair enough. Here's how I would approach the same situation.

I post my public PGP key if I haven't already, or even create a brand new one just for this purpose if I want. I ask the other user to use my public key to encrypt their email address and post the encrypted message. I decrypt their message to obtain their email address, which I can then send an email to. Obviously you can reverse the roles and ask the other user to provide their PGP key first for you to use to encrypt and post your own email address.

Bonus points if both parties share their public keys, so you can now encrypt all email communication, which is absolutely necessary if you are sharing anything sensitive since most email accounts are neither encrypted nor secure.

However, I appreciate my set up requires a degree of technical knowledge and your approach may be more suitable for non technical users.