Probably because nobody cares about Opera doing that since the ones pointing this out are at least privacy aware people that won't use Opera. It is also a problem when Brave does it because it is a "privacy focused" browser. They sure have the balls to do this.
Opera was also 100% up front about it and sold it as a feature. They didn't sneak it into installers and crap. IMO that's the issue, the lack of communication.
It’s crazy to me that people ever thought brave was “privacy focused” when it was clear that they were trying to jump on the crypto bandwagon with their own in-network crypto and ad network. It was always just a reskinned chrome with ublock built in and then their ad network tacked on top