MaBaya, in answer to your question . . .
Yes, even watching "ethical porn" is supporting the darker side of the sex industry. (To be fair, I struggle to see what the "lighter" side of it might be.) For starters, how can you be absolutely sure of the provenance of the porn you use. Like diamonds, it's not always possible to establish that someone wasn't exploited or abused along the process.
Also, it would be difficult to prove that NO PERSON involved in its making hasn't benefited from the exploitation or abuse of other people when making other porn that doesn't have the ethical "stamp." The money you pay for what you believe to be "ethical porn" probably contributes to the wage packet of some people, along with contributions from the production of porn that DOES exploit and abuse some people.
I suppose it could be compared in that way to someone who takes recreational drugs. They could buy their weed from a friend who's mate gets it from his cousin who grows it in his attic. If that's all true, you could convince yourself that it's not at all connected with human trafficking, burglary or other local crime, exploitation of workers in developing countries or anything illegal or unethical happening anywhere. It's just a bit of grass some guy's grown in a fishtank. But, do you know for sure that no one involved in the chain has any links to any of those other practices? Can you be absolutely sure that someone who also sells marijuana from this source doesn't also sell different drugs that come from other sources?
Basically, if you want to convince yourself that porn is harmless, or your use of porn is harmless, or your use of a certain type of porn at least is harmless, you'll be able to muster up an argument to back that. People who use porn that is pretty clearly exploitative and pretty clearly involves the abuse of other people still find enough explanations for why what they do is okay, so they can keep doing it.
If you are starting to have reservations, starting to question whether your use of porn is "okay," it probably means that you're starting to have niggles, starting to wonder whether the explanations you've relied on hold quite as strongly as you'd believed. I can't tell you what to do, but I'd suggest you do more research, look deeper into the issue, stick with the ghastly stuff that you'll find, keep your mind and heart open, and then see where you get to.
Other folks will hopefully come along with links to useful information for that process (but I've got some work things to do just now! :).) Good luck!