The problem is that F22 & F35 already cost US government hundreds of $billion. These planes must be at in service for 20-30 years to recover the investments. The US taxpayers will not support new investment in new planes untill they see these planes in service for 20 years.
The US millitary officials have to react to the J20 calmly because if they say the J20 is a threat to F22 & F35, then Japan, South Korea, Australia, etc will not buy F35, maybe not even buy the F22. So US military has to downplay the J20.
Anyway J200 is a bad news for US F22 & F35.