I made stuff that was maybe border line ethical, and I think ultimately it was up to what I could deal with, when I looked in the mirror.
If the mirror is giving you a hard time, then build something to contact the website owners who you are scraping, and give them an option for profit sharing, if any (you would be like an advertisement for them), and give them an option to opt-out. It should be easy to automate this. Just look for the contact or about page, and if a form or email or social site then use that.
Chances are, this will result in some work with no real gain, or loss, because most will not reply or not notice your attempts at contact. And anything lost can be used in your advertising yourself as ethical which gain new users.
Then you can say you tried your best and maybe the mirror will be somewhat kinder.