China helps Russia evade sanctions, likely supplies Moscow with war tech used in Ukraine

If it took US intelligence this long to realize this, we are truly screwed. China hasn't sanctioned Russia and as far as I can tell, hasn't ever agreed to support sanctions. I can't even think of a reason why anyone would assume that they wouldn't do business with Russia.
As a Historical note, sanctions have been the most ineffective move to change another country's actions and yet we still keep doing them. Castro's Cuba and Kim's N.Korea are still Communist AND Anti-American, Venezuela is still Socialist and Iran is still an Islamic State.
Oh, and almost all of Asia, Africa and Latin America are ignoring those very sanctions also.