It is true that venue lies in the jurisdiction of the crime, all other things being equal.
They aren't, here.
“You can move for a change of venue on grounds of prejudice, pretrial publicity, conflict of interest, etc.”
Certainly. But you are petitioning to change the venue, not change the district. The idea that the prosecution takes place in the district where the crime was committed is not just a standard practice, it’s a legal requirement under federal law.
Normally that’s not a big issue, since most districts cover an entire state where you can find a variety of venues, and some even cover multiple states or areas of states. But the District of Columbia is one single city, so there’s really no alternative venue there.