Re: Why do Mazda fake the data?
It's not just Mazda, quite a number of OEM's do exactly the same...
Hardware oil pressure sensors are expensive (it's fitted to every vehicle made) relative to the cost of a cheap software resource hacking in a look-up table (once in development, plus a few updates to tweak).
It happens with other sensors as well. I remember working on a turbo pressure gauge that was more show then anything else (Source was CAN with ~400ms period, no way that will keep up with the waste-gate).