Should this or shouldn't this be taught in Spanish?

[freeradical]

Since the second person plural form of verbs is only spoken in Spain, American teachers of Spanish do not cover this. The attitude seems to be, "well the students will learn this if they travel to Spain", and teaching this would make the class to difficult. Well, this conjugation is taught in French, Italian, and other languages without making the students suffer too much. Additionally, what if someone wants to read modern literature or movies etc. This just seems like some new teaching method that doesn't make sense.