For several reasons:
1. If you subscribe to a list then please please please take the time to locate the very clearly marked unsubscribe link, or use the one that gmail or your other email client shows. I spend a lot of time making sure it’s suuuper easy to unsubscribe. 2. Spammers know how to get around spam protections when they want to. They can switch domains and do other shady stuff a legit company can’t, so by marking my email as spam because it’s “easier” you’re not helping the fight against spam but rather hurting a legitimate email sender.
Now, if you can’t unsubscribe (because there’s no link, it’s broken, or simply doesn’t actually unsubscribe), and this is a legit company, please please please let them know.
If after all of this you still can’t unsubscribe, hit that spam button twice!