Call it what you will, using the Darknet is unethical. So is taking an extra 10 minutes of your employer's time at lunch, bringing home copy paper from work to use in your printer, using your cell phone while driving if that is against the law where you live, parking your car where you know you should NOT be parking it, even if you are 'just running in for a few minutes,' fudging on your taxes, and a host of other things that people 'rationalize' away every day.
Almost everyone has their own 2-3 little 'rule bends' that they feel are OK for them to do. It's just that some folks just don't need to rationalize them. They accept that they are violating some rule or law and call it for what it is.
When you get right down to it, Robin Hood
was a criminal!
Stitchawl