The thing is, GDPR has theoretically solved this in the EU. The UK's ICO is about to publish guidance prohibiting scraping public user information for marketing (where the user would not expect it to be used for that).

It's a really easy solution, because companies need to prove how they got your data when asked.

When you track the source of the mailing list you're getting spam from and they say "We scraped it from LinkedIn", they get fined.