Article 5 doesn't actually oblige NATO members

I do not share your interpretation (although I know that it has been the popular one recently).

I read it like this:

1. The obligation is out of any question: they "will" assist.

2. The goal of all measures is defined: "restore [...] peace and security".

3. The choice of measures isn't totally free. It must fit to that goal.

So, yes they can decide whether or not no use force, but they cannot follow random political agendas there.

And not fold paper airplanes instead of real ones :)