Conservatives: how is questioning the bad part's of our nation's history "unpatriotic"? or "Anti-American"?

I seen this insult get thrown around alot. then, alot of personal attacks as well, with consistent ad hominems, all subtly used to avoid answering the question directly. why do you guys do this? why am I "unpatriotic" because I think my country has done some very unforgivable evil in the past? it doesn't mean I hate the people or the land or the constitution...