And of course, it comes as no real surprise. Part of what makes their relationship so interesting and special was exactly this reluctance to identify it as such, and Merce was always particularly private. Mine might be a minority viewpoint, but I actually don't think secrecy or a post-Stonewall idea of the "closet" is the main reason for this reluctance. It was an aesthetic position, a well-known renunciation of any kind of expressionism--let alone an expression of love. I have little doubt Cage and Cunningham would have been just as silent had one been a woman.
But that doesn't mean we need to follow suit. While that might have been there aesthetic viewpoint, it doesn't have to be ours. I don't think it's violating their privacy to speculate on their relationship, since I don't think privacy is at stake. If one wants to figure out the Cage/Cunningham aesthetic, it is our job as historians and critics to look at what made these men think the way they did, and not be afraid to look beyond their often superficial public statements. As musicologists we are already constantly delving into interior worlds and private emotions, and we shouldn't be afraid to go farther. Merce himself put it well, in a letter from the summer of 1953:
When I phoned you, I couldn’t say endearments because of groups around, but I say them now, and miss you very much, and send you all my best love, and great kisses.