Are you proud of a country that gave orphan children radioactive cocktails to drink in a secret Government program?
*sigh*
A lot of self-flagellation in here.
If we're going by the "I can't be patriotic if my country did bad things in history" line of thinking you're going to be left with damn few countries worth being "patriotic" towards.
If you're German or Japanese, you should probably just kill yourself. In this line of reasoning, there's no recovering from that.
Same with Russia and China, and their horrendous gulags and mass executions of millions upon millions throughout the 20th century.
Or most of Western Europe's colonialism and exploitative, barbaric imperialism.
I'm all for objectively reviewing and studying history and mistakes and tragedies of the past, but acknowledging uncomfortable truths and learning from the past does not necessitate crippling national self-loathing.