$5 in Thailand might go as far as $20 in Dallas, which goes as far as $30 in New York. So if you take $30 from Mary in NY and give the equivalent of $20 to Jane in Dallas, is that unethical too? Or give $5 to someone in Thailand? At worst you could call it unpatriotic if you hire outside your country, but on a humanity scale its very hard to say its unethical or even truly understand the consequences.