But nobody is holding anything hostage. When you use Brave, you can opt-in to display ads on your Browser, and while doing so still get ads from Brave. So the choice to cut-off ads from the content publisher is yours. If you think it's unethical - just do not block the ads.
Using a piracy tube is also optional. That doesn't make the people running the privacy tube any more ethical. Brave is replacing a monetization scheme that the publisher willingly entered into with one where Brave inserts itself into the existing monetization flow and stops the monetization completely unless the publisher deals with Brave. Similarly, the tube sites stop monetization for its users unless the creators deal with them.