Were Knights just Mounted Infantry?
The difference between Mounted Infantry and Cavalry is the latter is trained to fight from a mounted position. Mounted infantry would dismount to actually fight. In the case of Speeder Bike pilots, as long as the fight was mobile they'd fight from Speeder. They could dismount and fight on the ground, but only if the battle required it.
You would need to read the post before mine to understand the point I was making. I think you are agreeing that speeder bike pilots aren't just infantry that use the speeder as a means of transport? Which was the point I was making. There's an obvious difference between soldiers riding to battle on a horse and dismounting to fight (dragoons I think they were called?) versus cavalry that road to battle on a horse and stayed in the saddle during the fight.