It depends on how you look at the numbers and what you feel the purpose of the taxes are. If, to take the two extremes, you view taxes as a being like a user fee - everyone pays the same amount to supply the same services - then uniform tax rates make sense. If you view taxes as being a way to make society more equitable, by redistributing some income, then "progressive" tax rates make more sense.

I obviously see it as the first.

When you got to a restaurant, they don't ask you how much you make and then charge you $3 or $30 for a cheeseburger depending on your answer.

In this case, as in most cases, the government should be blind and the rules should be applied equally to all citizens