Only if it's used to prove an argument.
Because, most of the time whataboutism is used in a very political argument, there is a heavy suggestion that If
eace is true, than Republicans/Obama/New Zealand/whatever are bad and people in my position, world view, political party are good. It is not a simple argument of if
eace is true, than this argument is a bad argument.
Whataboutism become relevant in this partisan environment. Because politics is a partisan environment. You can look at the argument in a completely closed system and a whataboutism is completely irrelevent, but as soon as it is brought into the political landscape EVERYTHING in the open system becomes relevant as well.
Because as a debater you can dishonestly look at the system as a closed system in order to make an open system argument... and if you do that in a biased way, a whataboutism is completely relevant.