The point isn't that education (in general) can't happen during a strike or that you can't get groceries (in general) during the strike you mention. The point is that education union is a small minority controlling what education is available, regardless of what the public wants.

To make your analogy similar, I think you could compare to grocery workers refusing to allow meat to be sold in grocery stores because a large portion of them are vegans, regardless of what the general public wants.