A) If you're going to make a point of defining inflation as something other than inflating of the money supply, why should people care? The only reason anyone pays attention to it is because of the long term downward trends - which are pretty much 100% due to monetary creation. Otherwise why, in practice, would the value of a currency drop? And why would this sort of "inflation" in Monero be an issue?
B) The [whatever]:XMR exchange rate is quite volatile, but that is measuring real fluctuations in the value of Monero depending on what is happening in the market today. Real value fluctuations are, by definition, not called inflation.
It is like saying the price of bananas experienced 12% inflation when there is a hurricane and a banana shortage. That isn't the right term - that sort of volatility isn't inflation.