I do not think that it is rude for a salon full of Asian nail techs to speak their own language. It would not bother me in the least.
As for the porn, I would have probably ignored it and laughed about that night with my husband. If this was truly "porn," and he was either an employee or owner, it's very unprofessional but NOT ILLEGAL.
If I thought i had received a good mani/ped, I would return without any hesitation.
~Who in the world am I? Ah, that's the great puzzle~ Lewis Carroll, Alice in Wonderland