This is rude. If someone doesn’t want your emails, you don’t want to send them emails. So make it easy to unsubscribe. Let them leave with a good feeling that will encourage them to come back if their needs change down the road. Fine print like this doesn’t discourage unsubscribing. It increases spam reports. As in “I’m getting rid of you one way or another!” and it makes people mad.
If my email list has only 10 people on it, I want it to be 10 people who want my emails and care what I’m saying.