Do Christians live by the "judge not lest ye be judged" concept?

Then why are so many of them worried about other people's actions, i.e. abortion, gay , etc.? As long as they (christians) are not personally committing sinful activity why should they give a fig what others do unless they are being judgmental which the scriptures clearly say is wrong and the reason they should not be judgmental is because they should focus on their own imperfections until they are perfect and then they can judge all they want..