It is for some people. I'm not telling that css-modules are bad in general, it's just nice to have an alternative. I know some people who are talking about css-modules as an ugly hack (though I don't agree with them).
True, cascade can be dangerous, but omitting it completely seems like a bold move — it's just a use case for cascade is very limited.
BEM is simpler to use because it's just a naming convention and doesn't require any tools (reBEM is just a set of optional helpers). It's also simpler to debug because with css-modules classNames are mixed with generated hashes, and with BEM you can clearly understand who is this className belongs to.
Yeah, you might be right with this one, maybe it would be better to have styles reset automated. Though in this case it's not really global, we use reset locally for certain blocks, not globally with tag selectors. Also, theme-reset is absolutely optional, it's just an example.
CSS modules are great and I personally like them. But BEM is just simpler, more familiar and more flexible. One of the main reasons people might consider to stick with BEM instead of css-modules is cascade. In most cases you can do without it (for example, with BEM mixes https://en.bem.info/method/key-concepts/#mix). But if you want to style internals of the component (for example, Calendar), cascade is much more convenient way to do that (ex: `.some-context__calendar .calendar__day`) instead of having a huge API of different classNames for all Calendar internals.