You are asking to see meticulous proofs in a simple blog post, which is not gonna happen. Also, any article like this will assume that you already know something about what's going on there, or at least in the rest of the world. Eg: If someone says 20-30% inflation rate is high, it's obviously comparing it to the inflation in other countries. So yes, it's damn high.
About the metrics, its pretty simple: they just pick the products/services that didn't increase much their price during that period. Of course nobody can't actually live with those products, nobody buys them or even know them. And when they need something real for the index, like the Big Mac.. Well, you know what happens. Automagically its price is reduced to a half, and the product is removed from the menu.
So, in this metric, 10% of inflation is high, right? and another countries can use a different metric, and in fact, they do. Each economy is different, if you cant produce energy by natural caracteristics of your country, your economy could be tied to international oil prices, for example. So comparing this things one to one is not possible. I want to make it clear again. I am not defending .gov.ar, but the way we are thinking these problemsis wrong.
Proof need to happen, in a post or anywhere else. Without that a rational decision cant be made, and we will never reach true democracy. The simple blog post as you call it is not only useless but harmful, because we use this information for actually making decisions. In modern politic, there is a close relation between knowledge, rationality and freedom.
