China's test created far more debris than any previous incident, including the US incident you point to. Furthermore China created that debris in a much higher orbit so it will take much longer for it to naturally fall out of orbit.
That single incident is responsible for something like 10% of all debris in orbit that is large enough to be tracked by NASA.
It's closer to 20% due to China's ASAT test and 80% due to the collective spaceflight activities of the entire world over the last half century. You know, vs. one single event.
If China dumped as much garbage into the ocean in one event equal to 20% of the entire world's ocean dumped garbage since 1957 you can be damned sure they'd catch some flak for that.
I don't know why people in US automatically think they have the right to do anything they want, yet when somebody else does the same they find every reason to brand them evil conveniently neglecting everything they did.
There is no point in trying to act innocent, space or other wise US has been screwing earth since decades now. Wars, weapons and emissions all in the name of development. Yet now when some other countries do the exactly all that for similar reasons, they become bad?
Did you even read the comment? One Chinese demonstration created 10% of all objects we can track. The US demonstration was held in a much lower orbit and most of the fragments it created have probably burned in the atmosphere by now.
That single incident is responsible for something like 10% of all debris in orbit that is large enough to be tracked by NASA.