You've hurt my feelings and destroyed my pride! No, but seriously, it's a "rule of thumb," not at all a rule. The amount people spend on interest and taxes varies wildly, as does maintenance and repairs depending on the initial condition and age of the property. If you have no idea, it's a guideline that might work for you. In other words, if you have a $200k house but rent for a house like yours is $1000, good luck covering all of your expenses.
I think I personally break the 1% rule because I rent out individual rooms and pay utilities. So while my "gross rents" are just above the 1% rule, it's "bad" because the 1% rule doesn't factor in you paying utilities. But I pay almost nothing in interest, have low taxes and all of my expensive maintenance items are behind me... knock on wood. (It was my primary residence for 7 years, so the repairs had to happen whether or not it was an investment property.)