With regard to the rainbow and Christianity please re-read Genesis 9 keeping in mind the context of the situation. so I guess read Genesis 5-9 with 9 being key to the rainbow. https://www.biblegateway.com/passage/?search=Genesis%205&version=NIV https://www.biblegateway.com/passage/?search=Genesis+9&version=NIV

What does the rainbow represent? What made God decide to wipe the slate clean with a flood? Why is it significant that homosexuals have chosen the rainbow to represent themselves in this context?

Queers waving the rainbow in God's face is a silly way to taunt him into action. I probably have a different view of God and Satan's relationship based off their interactions in the first two chapters of JOB https://www.biblegateway.com/passage/?search=Job+1&version=NIV https://www.biblegateway.com/passage/?search=Job%202&version=NIV

Forget that Job is the name of the man and look at how Satan and God interact here. It is as if the purpose of our life on earth right now is just a selection process for the next life and it is Satan's job to weed out the undeserving applicants like Satan is the H.R. department. The interactions between Satan and God here feel a lot like a morning meeting to me.

Waving the rainbow flag in this context is rejecting God and taunting him, although most who are doing this do not understand the context. This brings us back to the knowledge of good and evil and the question of if ignorance is an excuse which I believe it may be as all the way into revelation 9:21 with all that prophecy obviously happening it still notes that the people will not repent. They still have the option of repenting that late in the game. I believe it is set up this way for the ones who make the cut to not be salty about their friends and relatives and such being left out, but I am just a foolish man so please come to your own conclusions based on your study of the texts.
https://www.biblegateway.com/passage/?search=Revelation+9&version=NIV