Because rules always respect rights, and therefore must be accepted without challenge. All hail the rulemakers.
Sometimes you're not the rule maker, just the rule enforcer.
In our HOA, the original documents were written that it takes 80% of the homeowners - at a physical meeting - to change the rules. We have 372 homes in our HOA. It is hard to get more than 12 homeowners to ANY meeting. So we are stuck with the rules as written.
If you, as a city, wish to make an exception to your banner policy for "patriotic" purposes, go for it. Fully expect to have it challenged in court and cost the city thousands of dollars defending it. That cost will likely have to be paid with higher taxes, for which you will be blamed. Isn't this fun?
Too many of our “betters” telling the little people what they can and cannot do. Are there no potholes to fill?