a) There is a massive doping problem in the entire world of athletics - I could cite that study again, or cite Dick Pound and other insiders, but I don't want to go too far off topic.
You're entitled to your view that there is a massive doping problem in the entire world of athletics, I disagree, or at least I believe the proof coming out of Kenya - with endless doping failures despite utterly corrupt and abysmal testing standards - is far greater than any existing proof that countries like the USA and UK are equally doped up, at least as far as middle and long distance running concerned.
b) As I just wrote last week, the Kenyans are apparently worse than the average western country. Probably a lot worse. That's not just the current number of busts, but also the leaked IAAF suspicion/likely doping list, and the Seppelt leak from the year before that.
c) Specifically for the UK and US: Farah and Froome and Rupp and Gatlin may serve as living proof that UKAD and USADA still either can't or don't want to catch their cheaters. Same goes for Gary's wife and Armstrong in the last decade, for example. Nothing has changed in that regard.