The law does not say "cannot be enforced." It says, in general, no municipality may enact or adopt but does not provide for enforcement. Some communities are removing their ordinances and some activists are making hay and taking credit, but it is a purely political decision unless the state enforces the statute. It has not, to my knowledge, done so.
66.0409 Local regulation of firearms.
[ ...] (some deletions)
(2) Except as provided in subs. (3) and (4), no political subdivision
may enact an ordinance or adopt a resolution that regulates
the sale, purchase, purchase delay, transfer, ownership, use, keeping,
possession, bearing, transportation, licensing, permitting,
registration or taxation of any firearm or part of a firearm, including
ammunition and reloader components, unless the ordinance or
resolution is the same as or similar to, and no more stringent than,
a state statute.
(b) If a political subdivision has in effect on November 17,
1995, an ordinance or resolution that regulates the sale, purchase,
transfer, ownership, use, keeping, possession, bearing, transportation,
licensing, permitting, registration or taxation of any firearm
or part of a firearm, including ammunition and reloader components,
and the ordinance or resolution is not the same as or similar
to a state statute, the ordinance or resolution shall have no legal
effect and the political subdivision may not enforce the ordinance
or resolution on or after November 18, 1995.
I would say that a more real concern for openly carrying is the police abuse of discretion with disorderly conduct. Remember that the police do not 'charge', but arrest, detain, investigate and recommend charges to the district attorney. Police are not fired for no-charges but you will have to endure the legal process.
Welcome and best wishes.