If we got to see the people shortly before the flood would we see a bunch of sinful savages who constantly bow down to false gods and commit all kinds of sexual sins? If we saw the people of Sodom and Gomorrah would we see a ton of homosexual acts, after the English word "sodomy" derives it's name from this city.
I wouldn't be surprised if we saw these people we would just see normal people who know and vaguely worship the Lord our God and probably also know about the fall of man and that one day there will be a savior but these people still had Gods judgement one them.
Jesus said in Mathew 24:38 that people at the time of the flood were just eating, drinking and marrying and giving in marriage. Sounds like your typical "Christian", if Gods judgement for that time was a devastating flood what kind of judgement do you think he has for this dying earth?