A excepción de la reglas de "WIERDO" para el subjuntivo tensa , estoy adivinando que se usa subjuntivo como hablar con cortésmente . Como cuando se tiene que decir algo a una persona como " Escuche me , por favor " - Listen to me please.
Y tambien se usa el subjuntivo tensa para a hablar con Dios y he visto que se lo usa mucho en las canciones .
¿Dónde están las preguntas?
The 2nd person, formal (usted, ustedes) in sometimes referred to a the "polite" tone as it is what you would use in "polite" society. It is also referred to as formal, meaning it shows respect, etc.
From your example it seems, therefore, that you are saying that the 2nd person, formal, subjunctive endings (escuche, rather than escucha) is used to be more polite. Since we are speaking about imperative mood (commands) it really has nothing to do with the subjunctive mood, but rather, the use of the 2nd person, formal, rather than the 2nd person, informal. (the fact that they use subjunctive verb endings is irrelevant).
The subjunctive mood is used, however, with certain verbs to show politeness. The imperfect subjunctive form of deber, pedir, querer (debiera, pudiera, quisiera) are used to convey polite requests. And the nosotros commands (formed using 1st person, plural subjunctive verb forms) are considered polite hortations.
If case that have lost you, let me try to say it more concisely.
Spanish uses the formal, rather than informal tone to show politeness. The fact that the formal tone uses subjunctive mood verb endings only tangentially links the subjunctive mood to politeness. You could have just as easily said the imperative mood is used to show politeness (Oh, you did). It's not the moods, but the formal vs informal tone that shows politeness/respect, etc.