Renaissance culture was greatly influenced by the Neo-Platonic movement through writers such as the Catholic Marcilio Ficino, who I believe have relationships with men. It was by papal commission that he wrote his studies on Platonic philosophy.
It might not be possible, nor worth the time, to name names and get all the "dirt", but looking into the root of these movements will generally show where their fruit got it's nourishment.
Plato, as has been well documented, was guilty of pederasty, as was Socrates, and a good number of other Greek and Roman philosophers. The vast majority of painters during the Renaissance were involved more in philo-theosophical examinations than they were in adhereing to the Gospel, as can be seen by the fact that their artwork sought to mirror the Grecian ideal of perfect form. Da Vinci and the rest all used Grecian modes in their paintings. These works were often commissioned by private individuals, aristocrats, kings, etc. and although they used Biblical themes this often had more to do with the culture at the time than it did with any Godly inspiration.
There is a gnostic form of meditation, found in some mystical love poetry, where they sought to capture the passion (lust) illicited by contemplating (staring at) perfect forms (the human body) and use that to examine the "divine in man". Although not a painter, Gerard Manley Hopkins, also a pederast, used this in his "Christian" poems.
Too often it seems we are lead to accept things at face value and don't search out the root. Christianity has been the dominant force in Western cultural for 2000 years and it has been used to cover up innumerable heretical teachings through a facade of Christian imagery.
Eccelsiastes 1:13 - And I gave my heart to seek and search out by wisdom concerning all things that are done under heaven: this sore travail hath God given to the sons of man to be exercised therewith.
John 5:39 - Search the scriptures; for in them ye think ye have eternal life: and they are they which testify of me.