There are two dangers that go with this kind of love. One is that it will have the wrong focus (white people, e.g.). The other is that it is too extreme, too indiscriminate, too unconditional. At least some partial love has to be all right, I think, since it's very difficult to love without specificity. How can it be wrong to love my family more than others? If I cannot love my wife more than other women, then I cannot really love my wife at all. "Love" means different things in "I love my wife" and "I love all people." I suppose this isn't quite the same thing, but love of one's home town and/or country seems like a good thing to me. What kind of person doesn't love their home? But this love needs to be free of any contaminating hatred or contempt for others. It has no place for comparison. It is love of this, not love of this but not that or this as opposed to that. So it's OK (and even good) to love this place or these people, but not qua these-people-rather-than-those.
What about unconditional love, love of my country right or wrong? This too can be OK, I think, depending on what exactly is meant. Marriage vows talk about loving through thick and thin but not, as far as I can remember, with get-out clauses in case of serious wrong-doing. And it would be weird to want to insert such clauses. There should be more optimism and trust going in to a marriage than that. In that sense, love should be unconditional: there should be no need felt for reservations. If I were a lawyer I would disagree, but as a believer in marriage (whether same-sex or other-sex) I would say there should be no pre-nups. It's maybe slightly weird to think of love of one's children as unconditional, but that's surely better than being conscious of its conditionality. As I understand it, love involves a certain kind of commitment, similar to the commitment one might have to, or feel for, some moral principles, such as never framing an innocent person, never torturing someone, etc.
Must such commitment be unconditional in fact, objectively rather than subjectively, so to speak? No. It's important that we not frame innocent people. It's important that we feel absolutely committed to this principle. Is it conceivable that there might be a situation in which framing someone was the least bad thing one could do? Yes it is. Just as it is conceivable that the next cute baby you see might grow up to be a serial killer. But it does no good to conceive of this possibility and it is probably unhealthy to do so. Absent reason to think that you might need to change your attitude, your attitude should be one of unconditional, unreserved commitment to and love of what is good (this person, that place, that principle).
It's this same kind of health that's involved in the Nietzschean/Chestertonian love of the world. This love is not rational, since we can never evaluate the world objectively, but a patriotic, loving attitude is surely more conducive to well-being and good behavior than a jaundiced view.
But what if there is reason to think you might need to change your attitude? Well, then it's time for a re-think.
But if someone really thinks, in advance, that it is open to question whether such an action as procuring the judicial execution of the innocent should be quite excluded from consideration—I do not want to argue with him; he shows a corrupt mind. (G. E. M. Anscombe, ‘Modern Moral Philosophy’, Philosophy, 1958, p. 17)This is easy to misunderstand. What Anscombe means, I take it, is that some things are rightly out of the question for decent people. Framing someone in a capital case would be one such thing. Not loving one's child might be another (this is my example, not hers). But even these things can come into the question in the right (i.e. very bad) circumstances. That is not to say that they should ever be done, only to recognize that they might have to be considered if things got bad enough. What's wrong with bad forms of right-wing politics (the forms based on love anyway) is that they either love in the wrong, contrastive way, or else they love in a way that is willfully blind to some bad aspects of reality (or both, of course). This is the difference that Wittgenstein refers to in part II of the Philosophical Investigations (on p. 236 of the new edition) when he contrasts shutting one's eyes in the face of doubt (bad) with having them closed (OK). Love is blind, that's why I see this as an issue, but sometimes to be stubbornly blind is a crime. Determining when those times are, though, is certainly tricky.
Perhaps what I mean is that love of good principles and good places and good people should be unconditional, but not unconditionally unconditional. This sounds ridiculous, but the part about "absent reason to think otherwise" is important. Do I doubt the ground outside my building? No. And to do so would be crazy. In saying this, though, am I denying that people make mistakes, that natural disasters can happen, etc? No. But to have doubts constantly about such things would be insane. So in normal circumstances such doubts are out of the question. They only come into question when we do philosophy (or when an earthquake strikes, e.g.).
And I want to turn this into a sort of conservative principle: if it ain't disastrous, don't doubt it. Combined with a healthy primal loyalty to the world, this gives us something like an account of why McMahan is wrong. But perhaps we've had enough and better of those already.