I have occasionally come to the defence of CPI in several threads. What drives is usually that the critic shows little knowledge about that the CPI is and/or how it's actually calculated. There are real technical issues with CPI estimations. But forum and blog posts rarely reach beyond the level of "everything I bought/want to buy is getting more expensive faster than the CPI, so it must be bogus".
It triggers me in a similar way, I think, as comments like "my (sisters'/neighbours') kid got really sick after his vaccination, so vaccines are very dangerous". A small number of people really do get sick after (and sometimes even from) vaccines, and probably no amount of research will override their personal experience. But it's a bit disheartening if the level of discourse never rises much above personal experiences.
This is because media and government (in various computations) use CPI when talking about inflation, so it is natural for them to become used interchangeably.
Since CPI doesn't reflect inflation, it is natural to criticize it for failing at that. Maybe it was never meant to reflect inflation, but that seems about as futile as trying to argue for the proper, original meaning of the term "hacker", not what media made it to be.
It triggers me in a similar way, I think, as comments like "my (sisters'/neighbours') kid got really sick after his vaccination, so vaccines are very dangerous". A small number of people really do get sick after (and sometimes even from) vaccines, and probably no amount of research will override their personal experience. But it's a bit disheartening if the level of discourse never rises much above personal experiences.