We've never been nice to them.  We at first ignored the situation,  then we started with the axis of evil comments,  then with sanctions and tough talk,  and here we are. 

It would be nice if Americans actually reviewed their history with honesty instead of some sort of bias.   I'd bet 99% of the people here think N Korea got their nuke capability from China,  and have no clue China refused to help them, but Russia did.