Yea I know, it's semantics. The real reason that inflation of the Bitcoin supply isn't the same as inflation of fiat or even gold is that 1) as you pointed out, there is a terminal supply that we can all agree will never change and 2) Bitcoin is voluntarily adopted, meaning that unlike fiat money printing, we all agree that the miners should be subsidized at an exponentially decreasing rate.

Bitcoin is perhaps the only example where taxation via inflation is not a form of theft. The difference, as a libertarian would put it, is consent. There is complete consensus among all users of Bitcoin that its inflation rate schedule is important to fairly distribute the total supply, protect the network, and incentivize miners to process transactions until transaction fees alone can support this function.