It's better to have felt love and experienced the fullness of it and then lost then to have never experienced any closeness or warmth from another person. Even if a love was lost, it was felt before and therefore, it can be found again. Once person is loved once, though the consequences of heartbreak may be painful, it's better than turning into a cold, bitter person who has never learned the joy of loving or being loved.
You've made an assumption. People who has not experience love before does not necessarily have to be bitter and cold. Humans are grown to learn and to adapt to weight consequences and benefits. With all the growing stories of breakups, divorces and widows, it is very clear that falling in love is not a beneficial move. I will use a famous quote to make my point, "ignorance is bliss". People do not need to love, there is and only will be pain in love. I can promise you, there is no relationship that ever existed or will exist that will not contain pain. Being ignorant of love means there is no chance of being hurt or drawn in by the addictive nature of first love. Having to lose something that was already there, is a consequence that can be avoided. People are better off keeping a friendship relationship.