I am confused by how anyone who uses email to a significant degree could not understand that unsolicited bulk email is harmful. Sure, modern spam filtering is pretty effective, but any time a significant amount gets through, it becomes very difficult to use your email account for anything practical.

It doesn't take tech expertise to understand this, nor an especially advanced or specialized worldview to understand that breaking things for other people might be ethically questionable.

There's a huge difference between buying ads and straight up buying email lists...

I agree with you, but my whole point is that not everyone does.

Buying dumps of emails ARE a bad thing, even marketers know that.

As both a marketer and a developer, I can say that buying an email dump is NEVER something that I would do, but not its for the ethics of it (we all know marketers have no ethics). I wouldn't buy a list to spam because THAT list isn't MY list.

The hit/conversion rate on a list of random emails, or even semi-qualified emails, that you don't have a relationship with is so incredibly low, that it isn't worth it to spam their inbox, risking my reputation (opens & clicks to spam ratio).

A one percent uptick in spam reports is enough to downgrade my sending IP enough that my real customers would start missing my emails.

Real marketers aren't going to send a automated marketing email to a list of people they don't have a relationship with.

Most of the spam that hits my work email is people offering to sell email lists...