Tor is bad

Isn't tor just bad?

all that it did was enable people who would never have sold or used herion to do so thanks to black markets..

First and foremost Tor isn't about selling drugs.
The main part of Tor isn't used for that, Tor hidden services are, which are only a tiny fraction of the overall system.
Secondly, who gives a shit if people are buying and selling drugs? It's better than if they're standing on a street corner with a gang of thugs.