Battery Terminal Bolts

Has anybody ever figured out why the hell powersport batteries have that stupid nut arrangement rather than just having threaded terminals??? The bolt is ALWAYS too short to reach the nut unless you shove something underneath it.
 
I put my hand up and say that I have not just gone out to the bike and taken a measurement, but I am 99.9% sure in my mind that it will be M6.
Definitely not M8. That would far too big.
I've never come across a bike battery with anything other than either an M6.
 
+one
 
Has anybody ever figured out why the hell powersport batteries have that stupid nut arrangement rather than just having threaded terminals??? The bolt is ALWAYS too short to reach the nut unless you shove something underneath it.
Likely because the lead is soft and wouldn't hold threads well, and the use of posts with clamped leads like are used in cars takes up more space, which is at a premium.