I am a lawyer but I do not practice contract law and please do not take anything I say as legal advice. The language does seem concerning. With regard to what other browsers do, I can't answer that. What I can say, though, is that I am familiar with the social media site "Minds", where the user retains full rights to all content. In the case of a browser, the exposure to the entire web, rather than the closed confines of a site, may make ownership issues more problematic. For me, I would probably choose impervious as a Brave substitute, with the lightning network as a huge benefit, and avoid the other applications.