Presumably the point of the PE title is a reliable stamp that means "this person is a solid, educated, experienced and politically neutral individual who will keep your buildings standing". It isn't appropriate for engineers to weigh in on political questions about how people should live their lives in their professional capacity.
This is a lesson I suspect the software semi-engineering profession will learn when the cost of the political battles Silicon Valley is engaged in start to come due. Much like in religious contexts "be good" somehow morphs into "spill blood" when people try to control what others can and cannot do. Engineers should not go anywhere close to even the outskirts of that fight. Whoever wins it deserves a functioning, well engineered society.
Strong Towns is cool with me, but it is a political project trying to do good. That sits in tension with professional engineering. Engineers do good, but not with activism.