Earlier quoted context omitted.
I'm not sure why people would be wary of clicking the unsubscribe link on something they explicitly subscribed to in the first place. I mean, they trusted you enough to give you their email address to subscribe in the first place, right? The only scenario I can think of is when people didn't intentionally subscribe or were coerced into subscribing and those newsletters can go to hell and fully deserve to be marked as…
I've unsubscribed before only to find myself subscribed to a bunch of similar things instead. Clicking a link confirms your address reaches a person and is therefore worth spamming. Plus the risk of phishing. Plus the dark patterns in the unsubscribe UI.
I think this is received wisdom that might have been true 20 years ago, but doesn’t stand up to scrutiny.