Why? Because it is 'too rational' (in the straw-vulcan sense of not emotional enough)?

Because it's procrastination. The problem at hand is that one has trouble reading social signals. Any solution will involve lots and lots of experience (i.e. gathering enough real-world data for your brain to build the right mental structures). Trying to build a mathematical model seems like the sort of thing where you can put in a lot of work and pat yourself on the back for the effort, all while avoiding actually dealing with the problem.