Part of the point of organisations like Amnesty International is that they don't ignore transgressions by those who are, overall, in the right. Anyone who takes a minute to look at Amensty's website and look at their reports "[a]s Russia continues its war against Ukraine" (their words, not mine) can see they have continually called out Russia's atrocities in Ukraine. The fact that Ukraine are indisputably the victim in Russian aggression doesn't mean that their actions are beyond reproach - there have been well documented, if rare, cases of abuse of PoWs, for example - and it's right that Amnesty call out that when it occurs.
Now, I think they misjudged in the report that sparked this off, but the idea that it's a fundamental failing of the organisation? Nah.