¯\_(ツ)_/¯
The intent is to separate signal from noise (although which is which is somewhat subjective, Hacker News is liberal in that there are no guidelines to downvoting, so "signal" is merely that which gets downvoted the least) and to passive-aggressively reinforce forum culture, because more direct methods of confrontation will just get you downvoted, filtered and eventually banned.
higher levels are accumulations of hit points, all the while mods and demi-mods appear on occasion to level out grave injustices