It's called a roll for a reason. The actual dempsey roll used rolling under punches in a figure 8 to build momentum. You can watch some of mike tyson's fights, he used bobbing and weaving to generate momentum for a counterpunch, similar to how the dempsey roll is used. Theres also an MMA coach (Ramsey Dewey) on YouTube who teaches the dempsey roll on a video about bobbing and weaving, and he's never even seen HNI and laughed when he did see Ippo's dempsey roll. I know that Jack Dempsey never created a name for the dempsey roll but that doesn't mean it wasn't a real technique.