You have been profiled, and the profile works over time and across content. That data exists, and is sold to advertisers. The profile is about you, including private discourse between, say, you and family, and numerous research papers have shown it ties to exactly you even if it's supposedly anonymous. This is absolutely a privacy "issue" even if it's not clear to you personally how this might be a privacy breach.

That's far different than spam, where the messages are profiled, not the people exchanging them.