Anyone who says love "is really only" chemicals is telling a story. It is a story of disillusionment:
1. A loved one become unlovable. There's been a misconception, or lies have been discovered, or misfortune has intervened.
2. Love seen on its material side as ugly, ridiculous, demeaning.
3. A predominantly self interested life struggling after love and generosity and failing, then regretting the attempt, seeing it as impossible of success, wishing never to have asked for more than satisfaction of bodily needs.
In other words, the "really only" argument tells a story comparing kinds of life on the basis of the happiness they are likely to bring.
1. The "really only" argument encounters the American Founders' claim that democracy requires good people not to fall into faction, and that faction will destroy democracy because it encourages corruption and discourages cooperation. If you speak as someone who seeks to love and be loved, you speak as someone who leads a representative life recognizably like the lives of those who listen. Party politics won't be an obstacle to communication. Democracy is possible.
2. The "really only" story of disilllusionment, lies, misunderstanding, ugliness is capable of an opposing interpretation, in which the responsibility for all these story elements is one's own ignorance. Those who make this claim also claim they have the superior knowledge that allows the life seeking love to be lived and seen as obviously superior. They argue that those who have not experienced the life seeking love with knowledge how to do it have no basis of comparison of the two kind of lives, therefore their judgement is faulty.
"Anyway, I like it now," I said. "I mean right now. Sitting here with you and just chewing the fat, horsing -- ""That isn't anything really!""It is so something really. Certainly it is! Why the hell isn't it? People never think anything is anything really. I'm getting goddam sick of it."(from The Catcher In The Rye, J.D. Salinger)