Let me re-phrase your sentence to clarify my point:
Self-criticism is the way to the betterment of a society, only till it remains to self (own nation) and not mocked in front of others (other nations).
When you have a fight at home, you try to sort it out within home and not mock your own home in front of your enemies.
I hope it is clear now. Of course no one is criticizing self-criticism.