The only thing I can find is that in March of '22 the NY State Senate passed S7849 that did away with the need for a motorcycle endorsement to operate the Slingshot. Can't find anything changing it's registration status. Methinks somebody is blowing smoke up your arse.
I received a physical notice of non-renewal from Progressive, when I called them they explained the reclassification as to why, so this is indeed happening.