Well, it does seem a legitimate act of local government to require a permit
to take up public sidewalk space -- or street space -- as in parades,
picketing, selling hot dogs or newspapers, and displaying art.  If the
artist wishes to exhibit on private property, with the owner's permission,
then of course the government can impose no barrier.

If the simple act of getting a permit is impeded by government for reasons
other than public safety, then there is a problem.  e.g., that it interferes
with pedestrians, or autos, or creates some other problem that the
government MUST solve. Is that the problem outside the MET?

And, yes, the law has long been settled on the requirement that an
administrative processing fee (not a rental fee -- just a fee that covers
cost of handling) may be charged for such permits.

It's just a part of life in our democracy.