I know this woman, let's call her Helen, who has been single her entire life. She is now in her fifties and she says she is perfectlly content with her singlehood. Helen has a great career, many friends, she has lived in many different countries, and has tons of great hobbies. Still, many people insist on pitying Helen. I have actually witnessed "let's-get-together-and-feel-sorry-for-Helen" reunions where people seem to get together for the sole purpose of sharing with each other how bad they feel for poor, miserable Helen who is "all alone with nobody to take care of her." Even though Helen has been taking care of herself extremely well her entire life, people still enjoy discussing their fantasies of her misery.
Now, Helen herself seems perfectly happy. Probably for that very reason she doesn't organize pity parties to express how sorry she is for her partnered friends. The funny thing is that people who dedicate all this time to feeling sorry for Helen are in pretty crappy relationships. What would they do, I often wonder, if people like Helen didn't exist? How would they deal with the realization that their relationships suck if they couldn't take refuge from the sadness of their personal lives in the fantasies of miserable singlehood? "Well, at least I'm better off than poor Helen who's all alone," they tell themselves every time they feel their prized relationship is not that great.
Nothing, in my view, is a better measure of how people feel about their own romantic relationships than whether they experience hostility towards single people.