Let us look at an analogous situation: physical love.
In most societies, there are standards for when it is considered appropriate to engage in the physical act of love, whether these are explicitly stated or enforced through more subtle social pressure. A person who sets their standards higher still is often respected, while a person who sets their standards lower is usually reviled, and (depending on the society) may even be overtly punished for it... perhaps even killed.
There are people, for example, who have set their standards for physical love so high that nobody meets their standards. Their physical love is SO conditional that it doesn't happen. We call this being chaste or celibate, and this is considered by many to be a VIRTUE; a person who is unconditional in physical love is not permitted by many religions to serve as an authority.
On the other hand, there are people who set lower standards. A person who trades physical love for money, favours, or power is called a whore. They are reviled in part because they make a mockery of even the term 'physical love'... what they do may be physical, but it's not love. A person who sets their standards even lower can hardly be more respected: someone who will have sex with ANYONE, regardless of feeling, disease, violence, or even convenience or pleasure is usually just thought of as mentally ill at best. An object of pity, not respect.
Why, then, should it be any different for emotional love?
A love that is freely bestowed upon any taker without limit is worth about as much as anything that is freely bestowed upon any taker without limit, which is to say it is worth nothing. A college diploma that was given unconditionally isn't worth the paper it's printed on. A trophy awarded uncondintionally is neither a trophy nor an award - it is just a hunk of metal that symbolizes nothing.
Love can sometimes be the greatest thing of all. To treat it as if it were a worthless thing to be handed out for no reason could be thought of as an insult to all those who truly prize it. Those who proclaim the idea of unconditional love are most likely just those who cannot obtain love in any other way.
