Earlier quoted context omitted.
Are you sure that 100% of companies have not sold unsubscribed users information? As if there is even single counter-example you should just automatically mark it spam and then email providers should blacklist the domain.
You're absolutely incorrect about this. What you're saying may have been true a long time ago but it's 100% wrong now. In 2023/2024 you should click unsubscribe links. No matter how spammy a sender is, an unsubscribe click is a big signal that they don't want to contact that email account again. It takes time and money to warm up a domain, prepare it for outbound email, and keep it from being blacklisted when you're…
Plus the link is always at the bottom in a tiny footer.
The mark as spam button has no such issue and hurts the sender to boot.