Jebus. yuki isn't saying he can't see how horrible the U.S. is with this post. He's saying he can't see how Britain is anywhere near as horrible as the U.S. At least, the way he wrote it that's how it seems.
I fail to see how Britain can be nearly as bad as the US is.
The bold means he is comparing Britain to the U.S, not the U.S. to Britain. Meaning he already knows the U.S. is horrible.
Also I know nothing of what the British has done, but as far as I know every great civilization has some horrible wrong they have committed in the past. The U.S. has just committed a wrong more recently.