ph0rk
Friendship is Magic, and Magic is Heresy.
Your "point of the game" isn't everyone's "point of the game." You are applying your table rules and play goals to everyone else then anyone who deviates from that is a "cheater" or "unethical." Do you see the issue with that?
Further, the game defines the goals of play (D&D 5e anyway) as everyone having a fun and creating an exciting, memorable story by playing. This is perfectly achievable with some or all players having foreknowledge of the adventure. It may not be fun for you, but your sort of fun doesn't apply to everyone.
This is literally the logic that undergrads who cheat use when caught.