I think the comparison is, in the eyes of Blamemeta, between a thing that is very severe and a thing that is somewhat less severe. If that’s the case, equating the two must either exaggerate the severity of the latter or minimize the severity of the former. So I think Blamemeta is trying to say that it cheapens the severity of the holocaust, not realizing that the word “whitewash” implies that it’s deliberate, i.e. that Acharnien also agrees that Russia’s law isn’t a big deal and want to use it to downplay the holocaust. But I think it’s more likely they just meant to say “cheapens” instead of “whitewash” lol