Because anons stick around and wade through it.
If it was our common enemy in sure they would have left enough planted evidence to make it look like the US was responsible. It would be illogical not to. So I too don't get the hostility that has flared up over this. I'm sure the good guys would know it was a frame up so I have to conclude that either the CCP is complicit in these DS manoeuvres and happy for their population to be killed off, or that the CCP is just as you say and botched this badly and is trying to save face.
Normally Occam's Razor lands on the latter, but in this day and age it is very hard to tell.
I thought I'd seen it before, thanks anon.
Snap