Unsubscribing from these emails (Facebook, Twitter, idk, doesn't matter) is a chore, they make you go through lots of hoops and then they ignore the request and keep spamming you anyway. Also, by unsubscribing you're revealing to them that you are opening and reading those emails, which is something you probably don't want to disclose.
The best solution is to simply configure a filter in your email client so those emails go to the trash directly.
Before the apologists roll in: Cliqz GmbH is a media and advertising company, and Firefox DOES NOT own Cliqz GmbH, they just own a bit of it (officially they are a "minority investor").
The Mozilla Corporation sent private data of its users without their permission to a third party ad company. It's despicable and unforgivable.
Your decision to show ads to your users this last week without their consent was the last straw for me. And believe me, I've stood A LOT from you. My relationship with you has been practically abusive. Farewell Mozilla, it's been real.
I don't believe it's weird, in fact, I think it's natural. IPv4 is better (because every single machine and server has IPv4 connectivity, unlike IPv6) and available addresses are getting scarce. Therefore, IPv4 access with no CG-NAT is turning into a "premium" service.