You are mistaken. City ordinances absolutely comes into play here. In the US, you are subject to federal law, any additional state laws, any additional county laws, and then any additional city municipal-codes/ordinances.
Here’s the Seattle city ordinance that applies:
Seattle Municipal Code, Chapter 12A.10.130 Indecent Exposure, Paragraph A.
A person is guilty of indecent exposure if he or she intentionally makes any open and obscene exposure of his or her person or the person of another knowing that such conduct is likely to cause reasonable affront or alarm.
source:
This doesn’t invalidate my earlier statement that citizens are still subject to city ordinances.
There are around 20,000 cities and municipalities in the United States, most of them have public-nudity/indecent-exposure laws.
You successfully made the point that the legality of city ordinances can be challenged in higher courts (and even sometimes overturned) but the reality is that most people have neither the funding nor the time nor the expertise to take that up…which means ultimately you’re still subject to a city/municipality ordinances as well as state and federal.
In 2017, Tagami v City of Chicago, the US Court of appeals for 7th Circuit ruled 2-1 that the city’s public nudity ordinance did not violate the complainant’s rights and upheld the lower court decisions (which meant that City of Chicago’s ordinance remained intact and validated as enforceable by the city).
At the end of the day, yes you do have to be cognizant of the ordinances/codes of the city in question and cannot rely on State/Federal law alone.