How to describe a person who always prefers things from other countries but not from their home countries?
Solution 1:
Xenophilia
Xenophily or xenophilia means an affection for unknown/foreign objects or people. It is the opposite of xenophobia or xenophoby. The word is a modern coinage from the Greek "xenos" (ξένος) (stranger, unknown, foreign) and "philia" (φιλία) (love, attraction), though the word itself is not found in classical Greek.
Wikipedia
As suggested by @Monsoor, I should add the term for a person who loves foreign cultures, manners, and people is a xenophile.