In our culture, the rainbow is far too heavily associated with sexual depravity. Of course, the culture doesn't call it that. It calls it "diversity". But what it really is is the perversion of God's design. God designed sex to be a private act between a husband and wife, both as a beautiful expression of love, and as the method for producing more humans. But as with everything else, humans went ahead and messed it up. This is one of many sins that summons the Lord's wrath.
Ironically, the rainbow the wicked now use as an emblem for their proud expression of sin was originally designed as a sign from God. The sign of a covenant between Him and us: Never again will God send a global flood to destroy the Earth. The rainbow men use to glorify sin is the sign of a promise that God will delay their judgment.
Delay.
As Christians, we carry a very important message: That delay is temporary. He will never again flood the Earth, but water is not the only thing God may use as judgment. According to the Apostle Peter, fire is next (2 Peter 3:7). And sadly, all who are not on the "ark" that is the Lord Jesus Christ will perish in it.
But Paul gives us a glimmer of hope, ironically in a passage in which he speaks of their potential doom. After listing a few sins that preclude people from entering the Kingdom, in 1 Corinthians 6:11, Paul tells the Corinthians "And such were some of you. But you were washed, but you were sanctified, but you were justified in the name of the Lord Jesus and by the Spirit of our God." Mark those first words. And such were some of you.
So there is a way for the wicked to be saved. Of course there is! We were all wicked once. Every single one of us was once dead in sin, an enemy of God, and yet He called us to faith, and we were saved. And now He has given us another grace: We remain on the Earth as missionaries! We get to pass on the same message that brought us eternal life. We can call out to a lost generation, and we get to use the story behind their own banner to do it!