This is a game pack, so I'm assuming Strangerville is going to be a small neighborhood, not a fully fleshed out world like Windenburg, so calling it Strangetown would be a really bad move in this community. Under the name Strangetown, simmers would expect a new world, not a little neighborhood. It was smart to clearly differentiate between the two.
Edit: Just saw it will have 11 lots. Definitely not enough to do Strangetown justice, so it's a good move to call it something else even though the setting is similar.