Not true. Many states didn't even have "use / traffic" laws pertaining to ebikes so in general a compliant LSEB was conidered a bike for "use" laws in those states. Some states wanted to claim they were motor vehicles but that was posturing that would not have held up for even a single ebike ticket.
Translation: The states had laws that governed use, Ken just didn't like them and therefore they didn't exist.
Why does the recent DOI order pretty much state that all compliant LSEBs are to be allowed where bikes are allowed?
This doesn't help your case the way you think it does. The order still vests significant discretion within the land managers of the various locations under their jurisdiction to actually decide what actually gets opened to ebikes. We are almost 2 years past the order being issued and large pieces of land remain closed to ebikes, because the managers basically said "we don't think its a good idea".
A good area to use as a bellwether for DOI is the vast collection of MTB trail in and around Moab UT. Almost entirely on BLM land, remains open to normal bikes and closed to ebikes.