I think the ability to appreciate these things are written on the hearts of all, although all also have the ability to reject or ignore them. I think most cultures have honored these things to some degree, although I won't say all cultures have done so. Perhaps, I just being too cynical or unimaginative.
To some extent, whether all this is the product of a God formed in man's image, or just a spectacular result of a particular set of physical constants, is irrelevant.
Of course not. There is a reason for beauty, love and virtue and why they are good. And there is a reason why many loath beauty, love and virtue. Recognizing that there are reasons for these things is extraordinarily relevant.
A minor point of sensitivity. Why would you qualify God with "formed in man's image"? All it would do is get my, or somebody else's, back up and muddy the point you're making.
A lot of societies have revered truth and love and beauty and virtue, but not all have been Christian. I agree that one should ask why, and I agree that the answer is written on the human heart, but I think the search should be open ended. A large part of the world is not Christian, and probably never will be. There needs to be an ethical code that transcends the details of religious belief.
A minor point of sensitivity. Why would you qualify God with "formed in man's image"? All it would do is get my, or somebody else's, back up and muddy the point you're making.
Blame Voltaire. "If God created us in His image, we have more than returned the compliment'.