Distraction from the relevant point by bringing up cases where the accusee might be construed as having performed the same act as the accused. It's a distraction because it detracts from whether the accused did or didn't do the act. And the matter here is whether India did it; distractions away from this question are either implying that they did it ("so what if I did, you did too"), or an attempt to throw off and confuse the conversations about it.

It is important here because it takes away the moral high ground. It is also important because those who did it previously have not faced any repercussions, so why would anybody hesitate to do this.

I think people who use the word whataboutism do not understand the more difficult concept of hypocrisy. It's more difficult because it requires contextual reasoning.

"Whataboutism" is easy because it's purely syntactic, every time someone says "What about ...", you are allowed to accuse them of it--instead of having to confront, in good faith, an implied accusation of hypocrisy.

It's like Orwellian newspeak, but the new word is less expressive and more likely to confuse the disagreement.

I think people who engage in whataboutism and defend it with cries of "hypocrisy" do not understand the even more difficult concept that, even if you personally think that someone else is a hypocrite, it doesn't make you any less wrong.

Indeed, whataboutism itself is easy because it's purely distractional: "but Y is a hypocrite!" a defender of X may shout, when the topic is not Y, or their hypocrisy, but X, and what X did.

If your argument is that it was okay for X to do the thing, then you should be able to affirmatively say outright "I think it was okay for X to do the thing", and convincingly explain why, on a moral basis, it was okay for X to do the thing, without bringing anyone else into it.

Otherwise, it's like a child whining "but Stevie took a candy bar!" – maybe, maybe not, but that doesn't mean it's okay for you to take one, even if you think that makes someone a hypocrite