It does just not very well. Maybe the pine sap is more interested in being stuck to pine sap than soap?
There are things that are much better at cleaning non polar molecules off of surfaces, alcohols, gasoline, lye, brake cleaner etc, but they’re not great at cleaning your hands because they strip the lipids that make up your skin off.
Maybe for the same reason that you can remove greasy hair pomade (or other hard-to-wash-out hair products) from your hair by first applying a conditioner, then washing with shampoo. Supposedly the fats/oils in the conditioner bind to the grease and lets the soap get both.
There are things that are much better at cleaning non polar molecules off of surfaces, alcohols, gasoline, lye, brake cleaner etc, but they’re not great at cleaning your hands because they strip the lipids that make up your skin off.