It's not a question of judging a foreigner differently. Indeed there was a foreigner, one Pim Ligthart (Dutch) dropped from the worlds for exactly the same reason as Hayles. I'd say exactly the same about him. You'll note a lack of baying for the blood of said foreigner...
The thing is, a high haemocrit level is not *proof* of doping, it is merely an indication that there *may* be just as it's an indication that there *may* be ill-health and it's also an indication of dehydration. That's why, because it is not *proof* of doping that further tests are now carried out to establish the real reason for the high level.
Now, if the high haemocrit level of Rob Hayles and/or Pim Ligthart turn out to be due to doping, then as far as I'm concerned, they should be thrown out of the sport. BUT AS YET, DOPING/BAD REASON FOR HAVING A HIGH HAEMOCRIT LEVEL HAS NOT BEEN PROVED. It may well turn out to be an entirely legitimate reason(s) as to why these guys have a high haemocrit level. The rules are being followed and that's as it should be.