The explanation that you offered amounts to this: "the love that Christians profess to feel for Jesus is the kind of love that God feels for humans and humans feel for God." It's tautological. If you asked me what skepticism was and I said, "It's the activity that skeptics do," would you feel you'd been answered?
That was not even remotely the explanation that I offered. The second sentence of the article I linked says "the love of God for man and of man for God", and that is a translation
of the word, not an explanation. If you had some obscure Navajo word for skepticism, it would be perfectly okay to translate
that by saying "it's skepticism".
If you read past the second sentence into the greater body of the article, you will come across phrases like "a selfless love, a love that was passionately committed to the well-being of the other" and "If we could imagine the love of one who loves men purely for their own sake, and not because of any need or desire of his own, purely desires their good, and yet loves them wholly, not for what at this moment they are, but for what he knows he can make of them because he made them, then we should have in our minds some true image of the love of the Father and Creator of mankind."
But to get to those bits you have to read more than two sentences.
The assertion that I'm not capable of understanding the concept is a bit premature, since you haven't yet tried to explain it. It's also a bit ridiculous. There are many things with which I have no personal experience but which I understand perfectly well through the miracle of language. We have a rich and expressive language, supplemented by imagination. There's no reason you shouldn't be able to convey the nature of the feeling just as I could describe the nature of the feeling ai have for my mother, wife, or child.
The only tool that a lifelong atheist has to understand this kind of love is intellectual. As I said, you will probably never feel
love for Jesus unless you wholeheartedly convert to Christianity some day, which I think you will agree is unlikely. It's a bit like describing colour to a sightless person. You could say that red is light of a certain wavelength, and that it has certain cultural connotations, but that person would be unable to experience actually seeing
the colour red. They will be capable of only a broad intellectual understanding of what it's like to see the colour red.
I could understand what you mean when you describe the feeling you have for your mother, wife or child, because I have a mother and I have a child (I don't have a wife) and I have experienced the familial and romantic love (philia and eros) that you would be describing. I have a reference point. A lifelong atheist has no reference point
for understanding agape because they have never felt it, and never will unless they become religious.
I could say that agape love is completely selfless, that people feel it towards an entity that they believe feels it towards them, and that people who feel it will willingly sacrifice everything they have without any thought of reward, but those are just words. Words will be able to convey an intellectual understanding of what it's like to feel agape love, but they will not and cannot possibly convey the feeling itself.
The Wikipedia article on agape has quite a lot of words on the subject, and you have said that you consider them insufficient. I certainly can't describe it to you in better words than Wikipedia does. A good poet may be able to. Are you likely to be seeking out religious poetry for any reason?
So, since you claim to have felt it, why not have a go at describing it in your own words? Use as many as you want, use any analogies or metaphors or similes you need. The only thing I ask is that you not use the word love to define itself.
Excuse me - would you please point out exactly where I claimed to have felt it?