Most people are only willing to do something after repeated attempts because they're polite and want you to stop. If a website asks you whether you want cookies, you only click "yes" because the alternative is more work. If you constantly pester and threaten someone long enough, you'll always get a "yes" at some point. But that's not consent, which is why it's illegal.
Even if lawyers cost money, if I'm just expensive and stressful enough to stop people like you from sending even a single unsolicited message, it's worth it. Time is the most valuable resource we humans have, you've got no right to waste other people's.
