Lord, but these interpretations are a tortured load of old SHIT.
The chorus describes Modern Love, which is not homosexuality, btw, but rather more generally the sexual hedonism that arose in the late 60s and 70s - wife swapping, open marriages, school girl panties sold in Japanese vending machines, and the like. Really, the idea that one can be happy without love so long as there is plenty of sex.
The chorus lays out the dynamics of Modern Love and the metaphysical journey it inspires in the song's speaker:
Walks beside me, walks on by, ie, unsatisfactory to the speaker.
Gets me to the church on time, ie, causes him to seek meaning in religion.
Terrifies me, makes me party, ie, religion, too, is unsatisfactory, retreat to hedonism!
Puts my trust in God and Man, ie, still feeling empty? Have a go at humanism.
No confession, no religion, don't believe in Modern Love reiterates the vacuous nature of the loveless existence.
Leading up to the chorus are simply short statements of ennui: Things don't really change in a world commanded by those who profit via the power to charm. The speaker has looked behind the wizard's curtain and found Oz lacking. Imagine someone who once thought Andy Warhol was brilliant but then a decade later began to have misgivings that it was just a fucking soup can competently rendered by a fortunate idiot.
That's the gist of Modern Love. And though there isn't much explicit reference to aging, I'd posit that Bowie was thinking about growing older at this point in his life and that is felt in the song with the whole "nothing new under the sun" vibe. Bowie at 36 suddenly wanted to make a shitload of money, to be a celebrity, to be well accepted by the mainstream. Something about the way he'd done things for the previous five years - years we fans consider a creative zenith for him - dissatisfied him. If you accept this, then Modern Love could be construed as a buoyant farewell to the creative dead end the Berlin trilogy represented. In some regards, he may have feared Warzawa was an aural Campbell's Soup can and felt a compulsion to break free from it.
Kid, you've paid your dues...dues and dues. ~J. Tweedy