I think the major reason Chicago goes D is that after Celebrini, the three Fs (Demidov, Lindstrom and Iggy) are pretty much equal to the six Ds in terms of expectations, and next year the draft shift to being forward-heavy. Chicago will be a bottom feeder again, and will be able to choose a top forward to play with Bedard. They will take Lev or Dickinson IMO.
D takes longer to develop too which should be a consideration when rebuilding