I don't normally like making pop culture references, but with this topic I find it too tempting. Ironically, however, the famous song by Haddaway "What is Love?" doesn't actually answer the question, but is simply a very catchy song - no surprise there.
Love is something that we talk about a great deal today. It's a word especially present in social movements which try to promote tolerance & acceptance of certain behaviours or persons. And indeed, as Christians we are called to love the Lord our God, and to love our neighbors as ourselves.[1] But what does it truly mean to love somebody?
Perhaps the biggest mistake is to confuse the objective act of Love with subjective taste. This is not surprising since generally we find it difficult to put our finger on it, having no formation on the matter. As a consequence, we believe that Love is simply a more potent act of liking something. The confusion is only exaggerated when we say how we love a given food, when truly what we mean to say is that we like it. We're taught since we're children this erroneous scale of: hate, dislike, like, love - although hardly ever do we hear people use the word "dislike" anymore, which considering the true meaning of Love (and therefore Hate), I hope that my dear reader will learn to appreciate the word "dislike" after this. It is perfectly possible to dislike a person, and still love them. In fact, with regards to people, we often go through phases of liking and disliking the very same person. Yet, at all moments we can still love them. This is precisely because liking and loving a person are not the same or even related. Love, properly speaking, is a desire for Good (for oneself or another).
With this definition of what Love is, we are able to truly comprehend what it means to love the Lord our God, and (especially) to love our neighbors as ourselves. We must love the Lord our God because He simply is Good. We must desire Him because He is Goodness itself. What's more, all goodness we may find in this world is nothing more than a pale reflection of God's perfect Goodness. Therefore, we must love God, perfect Goodness, above absolutely all earthly goodness which is simply a pale reflection of Him, loving earthly goodness as what it is: an imitation of Him. In other words, loving God is the same as saying we desire Goodness in its most complete and perfect form, which we can only achieve when we are in full communion with Him in the Celestial Kingdom.
Now, using this same concept we can discover what it means to love our fellow Man: to desire Good for them. If I desire Evil upon someone, I don't love them, I hate them! As such, it is possible to dislike someone but still love them, just as it is possible to like someone but hate them. Both of these sound rather contradictory, but they are more common than you may think. For the former, consider all those people that you may personally (and therefore subjectively) dislike in your life. Do you wish Evil upon them? Do you desire for them to be harmed? Well, perhaps for some you do, and you could properly say that you hate those people, but my guess is for the vast majority of the people you dislike you don't wish these things upon them. In fact, there may be some who you truly love despite disliking them, and wish the best for despite how you feel about them subjectively.
The latter of the two, liking and hating a person, is perhaps the one that seems the most contradictory, and yet it is (in my opinion) the most common. This would be subjectively finding a person enjoyable, while at the same time desiring or preferring Evil for them. Of course, this hardly ever takes the form of truly wanting to actively inflict harm on this person, but rather its most common and insidious form is in that of omission, especially omission of correction. That is to say, when we value our personal convenience and our amicability with the person over their own (or our own) good - i.e. effeminacy. This mentality of hatred runs rampant in our current era, and irony of ironies it is often referred to as love. That sin of omission which is the toleration of Evil, which constitutes an act of hatred against our fellow Man, is called love. In reality, this is nothing more than egoism.
As such, we can conclude that toleration of Evil is not an act of Love or Charity, as some would have you believe, but all the opposite. Toleration of Evil is an act of Hatred and an offense against Charity, and therefore an offense against the Almighty God. You are not doing good by your fellow Man by permitting them to persist in their error, you are condemning both them and yourself, for molles regnum Dei non possidebunt.[2]
Gospel According to St. Matthew 22:37-40