Don't feel like typing a novel, but her argument is trash, and easily combated.
Put as simply and summarized as I can, being able to trace wrongs, (and I'm taking the position at face value), doesn't alleviate those that play into the wrongs following its beginning. So if I start pillaging countries, and I have underlings or people are inspired to do the same, they are not alleviated from the causes of their harm simply because I initiated it or inspired them to do so, even if they are the first to recognize it as wrong and as a result, outlaw it.
You see, when you commit a wrong out there, it is already done, plain and simple, you can't ever really rectify that, but what we can do is compensate the affected parties to the best of our ability. In engaging with ethics, we strive to prevent wrongs from happening, because rectifying them is truly an impossibility if we analyze it properly, which is why I'm keeping this post short because something as simple as striking someone, I could type a whole report on that alone, so think about something as complex as colonialism, in truth, if put to a dollar amount, the country couldn't exist if they paid back what was truly due. And why should they pay it back? Well this plays into our moral systems and maintaining consistency, it's what I would hold them to as a means for getting agreement on reparations.
Trying to keep it short...
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Side note, another example of why Lemon isn't fit to be hosting his own show, not to suggest he is an anomaly amongst political commentators, in truth, 99% if not all that I am aware of shouldn't have their platforms, they haven't engaged with philosophy enough or even the topics they discuss to justify their airtime, it's the media, really just money, that justifies their airtime.