That’s because Microsoft GitHub is a proprietary monolith. Compare that to the open core & self-hosting of GitLab the more FOSS-positive space where each server (without federation) requires a new sign up, confirmation emails (meaning you already had to go thru email), CAPTCHAs, setting up new keys, etc. That said, you will need to get your email filters in place or you can get a lot of new, unwanted mail (assuming you are required to sign up which often isn’t the case).
Personally, it's not. I'm using GitHub and I also sometimes send patches in emails.
I'm asking specifically what part of subscribing to mailing lists is the tricky part, as that's what parent mentioned. I'm not saying it's easier/harder than GitHub's workflow.
