If they don't want to make it easy to unsubscribe me immediately I just report it as spam. Hopefully that goes into Gmail's whatever "big data" of spammers and starts getting them classified as spam across the entire network.
Can't speak for Gmail specifically but we ran a biggish email operation a few years ago (sending real estate alerts) and were notified when some of the big providers users marked our emails as spam.
So unless things have changed, the newsletter providers are notified.
If the newsletter appeared from nowhere, then yes, it's spam.
Go away Janice, I don't need an extended vehicle warranty, and no I didn't contact you for information.
Any of those have been demonstrated to be capable of spectre/meltdown/etc. Hope your passwords/ssh keys aren't stored in RAM.