The sheer amount of recent MongoDB hate has been extremely annoying, not to mention the half-assed reasons for justifying it - we've learned a lot of things from running MongoDB at scale, and none of them are what the haters usually whine about.
I think that MongoDB has got a lot of attention because its brand of NoSQL is one of the closest neighbours to RDBMS. I believe a lot of people may have dabbled with mongo and they might have walked away realizing that NoSQL is not 100% sugar plums and lollipops as evangelized. There are trade-offs between different NoSQL databases and RDBMS, and Mongo is no exception. Personally, I really like MongoDB and continue to use it.