Oh, that's a nice bundle of sweeping statements. Let's respond to some (I have [numbered] them in the original):
[1] English spelling is a pain, to native speakers as well as to students. The problem with reform is that there are so many diferent dialects (in America too) that it would be difficult to single one out to be the basis for a more phonetic spelling. One advantage of the present system is that it is, admittedly after many painful hours at school, readable by speakers of all dialects. And don't forget that, although AmE has a few more logical spellings than BrE, the overwhelming majority of words are spelled/spelt in the same way by speakers of both dialects.
[2] That is your opinion. I don't agree.
[3]. There are many good reasons for studying AmE. There are also many good reasons for studying BrE, and indeed for studying several other forms. And if the learner's well-considered choice is for studying BrE, then that is one reason for not studying AmE.
[5] If, unlike the American government and immigration authorities, you believe in complete freedom of movement of labour/labor, then I suppose you could say that.