This is such a dumb policy, and it's absolutely not even being followed.
I submitted a timer app this year and it got approved. It's literally just a slightly more feature-rich timer.
I made this as a "my first app" type of experience. Never at any point was the quality of my app questioned, and I'm the first person who will tell you that it's not very good.
Don't worry. The next time you spend lots of time developing an app, Apple will be sure to reject it multiple times ;p