"does he thinks that at least object oriented programming is more naturally understandable by developers? The question is about how they might use, say, OO DBs with more understanding. may we say that OO approach in programming is much less alien that map-reduce things? because if we say 'people don't understand', then they might even don't understand some other part of their programming job."

OO is not natural, in my opinion, it is simply popular for a variety of reasons way outside the scope of this interview. There is no free lunch: regardless of paradigm, the best developers have a deep understanding of what is going on inside and under their applications, where that includes things like the databases on which they depend, the networks on which they depend, etc.