I'd say a coincidence. (if going by overall popularity.)
I got an impression somewhere that using Angular is hip right now (or was less than a year ago). It seems web development goes like that, some technologies become a hip thing to do and this changes often.
Do you ask because you are more familiar with React, or do you feel React is simply superior?
I was just curious to be honest. I am familiar with both and prefer React. Also it would appear (based on what we can see as users) that React would probably have been a better choice. That said, there is quite a bit more that we don't see, so my question was kind of silly and meaningless I guess. =) But yea, just idle curiosity.