I think its because we all define it differently. I think that love is just another word for the desire to promote the welfare and happiness of someone else. Simply put - the extent that we're willing to go to please someone else.
It can be conditional or unconditional.
It can be conditional, depending on the actions of the target. For example, when you're willing to continue caring for someone if said someone also cares for you.
It can be unconditional, such as when you care for someone and wish to do the best for said target regardless of his or her actions.
It can be romantic or platonic.
It can be romantic, involving emotions of attraction and desire. It means or involves that you'll like to have sex with the target of attention someday and would find emotional gratification from that.
It can be platonic, completely divorced from all emotions of attraction and desire. It means that you desire to promote the welfare of said target, but would not find emotional gratification from having sex.
This combination actually accounts for most(but by no means all) types of love.
When love is unconditional and romantic, this is the idealized love portrayed in literature, most likely because writers and poets had a tendancy to be unrealistic in their expectations. While the extent of attachment can vary, this definitely relies heavily on trust on the other partner because its not hard to see how it can be dangerous to the lover. The simple, "If you love me, then you would do X" is a great example of how unconditional love also implies a certain submission and negation of yourself for the sake of other person. It also allows self-validation by the other("All that matters is what you find me beautiful","I can't survive without you"), redefines the self in terms of the relationship("I want you to be my first, my last, my everything"), and tends to believe the relationship is the result of destiny or otherwise magical forces. When love is unconditional, romantic and not returned, then it is unrequited and can be incredibly painful.
When love is conditional and romantic, it could be seen as somewhat selfish, but it is often perceived as "healthy." Most often, this is when you love someone and continue to emotionally invest yourself in someone when it seems likely that you'll also be able to benefit from it. This usually involves emotional boundaries on both parties("She does not measure my worth as a human being"), sets rules on the relationship("If he cheats on me, this relationship is over"), and tends to believe that the relationship is the result of purely casual forces.
When love is conditional and platonic, it covers many of our interactons with the world. Most of us are probably well-intentioned unless given reason to believe otherwise. Again, it involves boundaries, rules, and a nonmagical understanding of the relationship. I probably wouldn't kill anyone for my male friends to make them happy, but I would be quite likely to fight or even kill someone to defend them from harm.
When love is unconditional and platonic - well, first, its incredibly rare. Its typically a kind of filial and familial love, where you're willing to do anything for someone else without any romantic or sexual interest. I've experienced it only once(maybe twice?) and it wasn't from my family - its incredibly rare, but it does exist.
Regards,
IO
