Flask requires a lot of other stuff, and most people choose to use it with this other stuff highlighted on the page, but one can very well choose a different set of stuff.
Personally, I don't like the idea, but the term "micro framework" is not meaningless.
I like Flask but the first time I tried to use it and found it had all these dependencies I was disappointed. It kind of reminds if of when it was fashionable for people to post headlines like, "I wrote a blogging platform in 5 lines of code" and when you go look at it they used some massive libraries which are of course much more than 5 lines.
