system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry potter] Why are the three unforgivable curses, the only unforgivable curses?

It's set up that these three spells are the spells you aren't able to cast, legally. Are these the only banned spells, or just the most famous? 

Surely combative spells, resulting in a pain filled demise, would be regulated more so than one that did so painlessly. Especially where ghosts are a thing.
gpt
The Unforgivable ones are so named because of how specific the punishment is: if you use one on another person, it's worth a lifetime sentence in Azkaban.  

Any other curse has some more mundane use or can be legally used defensively.  So at worst, you could be put on trial and judged based on the situation with any other spell.  But with an Unforgivable Curse, your trial would just be to prove that you *used* the curse on a person, and if found guilty, it's worth a life sentence.  Unless you're one of the few people allowed to use them in specific situations, like Aurors.