F=m*a. Expecting constant acceleration with increasing mass, increases the force required to achieve those accelerations. A motor applying high forces gets warm. Even if it just slows down the print, that still gives the motor more time to cool off.
From what I've understood, Cura isn't just meant for ultimaker printers, but rather a quite general purpose slicer. I might be wrong though, but supporting bed-sligners isn't exactly a bad idea for them to keep more people in their ecosystem.