How is it hostile? Serving you an ad when you don’t have a tab open? Literally open a tab my guy it’s free

Many opponents of Brave online are thoroughly convinced that Brave Rewards (which gives you their Ethereum coin in exchange for showing ads as OS notification) is on by default, when it isn't. They also claim that this replaces blocked ads on webpages (this may have been true very early, I didn't use Brave back then).