Inflation is a change in the price level, i.e. an average. TFA argues that inflation is misleading because prices don't change uniformly, and therefore inflation doesn't fully explain every change in the price of every possible commodity and service.
I think it's a straw man argument, because nobody claims that inflation fully explains changes in the prices of commodities. Instead, measuring inflation allows us to decompose these changes into a general component (i.e. inflation) and an idiosyncratic component (i.e. a change in relative prices), which is useful because it gives us more information about the causes of price changes. Inflation is only misleading if you're willingly misinterpreting it.
I think it's a straw man argument, because nobody claims that inflation fully explains changes in the prices of commodities. Instead, measuring inflation allows us to decompose these changes into a general component (i.e. inflation) and an idiosyncratic component (i.e. a change in relative prices), which is useful because it gives us more information about the causes of price changes. Inflation is only misleading if you're willingly misinterpreting it.