I think people are misremembering or misunderstanding a recent controversy where Brave was adding their own affiliate links to the user's browsing session without the user's knowledge or consent: https://www.coindesk.com/brave-browsers-affiliate-link-contr...
These points had been true at some point though... Also, brave is constantly astroturfing, so you should always take whatever you read online with a grain of salt.
I used brave's android browser a long time ago as well (at that time these claims were true - but they didn't replace the ads on all pages). I cannot speak about whats the current situation however, as I'm not up to date on the topic.