Are you a native french speaker? Maybe you heard it differently from me, but while I am all for nuance, lets not sanewash people and take them at their word.
I use plenty of software where the developers are not primarily focused on security, but his line of reasoning sounds just plain dangerous for an OS developer. Maybe he phrased it bad, but that would be up to him to clarify and we shouldnt do that for him.



If you are willing to have all your accounts linkable by the signup email, you dont need a temp or relay email service at all. Just sign up for a single random email address somewhere that lets you do it anonymously.
I am happy with addy.io and havnt had any issues. You could maintain a few providers - throw in ddg and mozillas services - so you can try from lots of domains I guess.