I believe the main debate there is about network security: Which is the right tail emission number for maintaining security? Tail emission will be too much (for network security) with high BTC price, and will not be enough (for network security) with low BTC price. Future price is unknown, meaning you cannot find that number, meaning it will always be seen as arbitrary. I prefer 0 tail emission.

To understand inflation, you must first understand fractional reserve lending and monetary elasticity in a bank-note system. When a bank issues you a loan, they are not issuing 'money', rather it is you that are trading a promisary note (future value) for a balance on their books (present value). The bank, as the servicer of the loan (debt collector), guarantees their depositors that they will be immune to the bank's inability to collect on the loan. And if you (the lender) can't pay the loan back, the bank guarantees their depositors they will remain solvent for various reasons (e.g. loss taken from profits, central banking, FDIC, etc).

Inflation occurs when you default on your loan and the bank cannot collect on the loan. You have spent this money (present value) you generated by making a promisary note (future value) and trading it for currency that did not exist before you made that promise to repay. As soon as you default, and you never repay it, that money (present value) will never be collected to pay back the loan (the future value of your promise is destroyed) and therefore inflation.

This is why its nonsensical to create a digitally scarce commodity that inflates indefinitely simply for the sake of thinking that a money needs to be inflationary.

The only purpose algorithmic digital commodity inflation could serve is to reward a certain class of participant by receiving the issuance before anyone else. This is because there are no trust relationships built into the system, no lenders, no creditors, to debt collectors, therefore it is necessarily a hard money. In effect, a trustless system would necessitate issuance through the miners. Bitcoin was designed to reward miners in this way as a means to issue the currency by way of securing the merkle-root ledger. If the transaction fees turn out to be to low after the block reward falls to effectively zero there might be a rationale to use an inflationary polify but in the case of bitcoin this need is very unlikely.

TIL: BitcoinTalk can still be a useful source for information.