I don't see anyone comparing it to costs in the US. The US dollar is still one of the most leading currencies used for trade, and it makes sense to convert to US dollars for the figure to be meaningful outside Russia. Though again, Russia and the US are not quite on par, as the US is 25 on the list with a lower Gini ratio as of the latest data point from 2021. I don't know why you keep shifting it from one subject to another. Just like bringing up the US has no relevance to someone being arrested in Russia, income inequality is not as relevant to my point about wealth inequality.
Edit: Also, if you were 100% in the right on this, the conclusion would then be "Average salary is a poor metric for the US too". OK. So?