Combinations of words have different meaning from words alone.
If it is the "entire county" paying, then that is the same as the "county" paying and "entire" is redundant.
On the other hand if "entire county" (all the people) is not the same as the "county" (governmental entity representing the people), then in this context "entire county" is untrue as revealed in the article where at least one citizen is on record opposing it.
"The map is not the territory."
Suppose you reside in an Irish county in the UK and the County elected officials decide to erect a statue park, all of the statues being of Margaret Thatcher. Would you say you supported that? Probably not. So it would not be the entire county supporting it or erecting it. Yes, the entire county tax base would have to pay for it, but some would do so under protest if you asked them, perhaps even yourself.
Or would you be glad to be included in with all the rabid right-wingers (Conservatives)?
Probably not.
Further, the word "Join" in the headline implies that the people who paid ("entire county paid" ) are joining. They are not. The entity that represents them (the "county" ) is joining.
The entity representing the people is not in the same class or level as the entire population represented by the entity. Nor is the tax base the same as the populace or the voting populace. Similarly the map represents the territory but is not the territory.