I agree with OP. I've gotten used to it, but it still creates unnecessary mouse movement and clicks.
I don't know how many photogs would actually work from different folders at once, unless they have some overly complex organization system. For me, everything from an event goes in a folder and I work on that event. When I'm done with that event, I move on to the next event, which is in another folder.
Assuming people are going to be working on many folders at once was like most other assumptions.
Based on the many advanced programs Adobe has on the market, I don't buy into the "they couldn't figure out how to let us choose."
For the record, I like Lightroom...mostly. I just don't like the defensive excuse-making.