Limited resources.

You have X amount of grit to cover Y number of roads or Z number of pathways. Which has more traffic and which is more prone to fatal accidents without grit?

Obviously the roads are going to get priority and even then with footpaths which ones are priority to be gritted the one down empty street or the one outside a school?

It's not sexism it's prioritizing resourcres and managing risk.

To give an example here the first thing that get's grit is the biggest roads and paths to emergency services like hospitals or fire departments. Then smaller roads and things like common routes to schools and so on.