There is difference between “Mongo’s documentation sucks” and “Mongo is technically deficient”. The former can be corrected by updating the documentation.
Yes, I agree as far as the end user is concerned, they are losing data either way.
I think the implication here is that "Mongo's documentation is deliberately bad in order to hide their technical deficiencies," i.e. they're hoping people will use the defaults, be impressed by the speed, and never realize until it's too late that they're not getting the consistency they were promised.
Yes, I agree as far as the end user is concerned, they are losing data either way.