Hacking and cheating are different things.

Hacking is looking at the rules and finding smart ways of following them. A lawyer or accountant finding legal loopholes is hacking.

The clearest place to see hacking is within games where one follows the rules and does not cheat.

Avoid thinking that hacking is unethical behaviour. A common mistake of people that don't understand the culture.

Like many great words, the meaning does depend on who uses the word. But the people who created the usage didn't use it for cheating.