P.S. And yeah, I do recommend you to check the website for trustfulness. This list is intended for good guys who respect people rights of privacy.
I'm familiar with at least two of the services on your block-list - because I actively use them. Neither of them is limited to "one time emails". One provides addresses that forward until you disable them, and the other allows a specified number of e-mails, with the option to either renew a sender's e-mail quota or set them as "trusted" (allowing unlimited e-mails). I only disable these disposable addresses as a last resort - if I start receiving a high volume of e-mails that I did not agree to receive and can't unsubscribe, or if I see that the address has been shared with a third party without my permission. If you treat me with respect, you'll be able to contact me for as long as I use your site. If you violate my trust, you'll be treated as a spammer.
This is The same argument against DRM. It hurts the legit folks and didn’t impact the pirates.
Don’t build barriers for the people you want.
If a user doesn't want you to be able to reach him out, he absolutely should have a right to be able to do that.