Matter is not a force. Matter and forces are two different things in physics.
And the "strong force" is another thing altogether.
I think their point might be that matter is what defines the location of the force field. I.e. it's the EM field doing the actual work.
That is, until we find a way to unify the fields
I think their point might be that matter is what defines the location of the force field. I.e. it's the EM field doing the actual work.