He is referring to is the finite supply. In 1960 the entire US monetary supply (M2) was $300 billion. Today it's $22 trillion. When there's so much more money out there inflation is inevitable. Monetary velocity is the true driver, but greater supply tends to drive greater velocity.

By contrast sometime around 2140 the final Bitcoin will be mined, and we're already reducing the number mined per block. Inflation can still happen for reasons besides supply, but it's generally much less probable.

My post was not stating that digital currencies are inherently, "magically" non-inflationary.

To me, it sounds like someone is either ignorant or arguing in bad faith for them to suggest that there are no digital currencies which are non-inflationary. BTC will never exceed 21 million bitcoins in circulation.

To address your other concern - the "problem" being addressed is a private company seizing your money over the contents of your speech. With self-custody of digital currencies like Bitcoin, it is not possible for third parties to expropriate your funds, provided you have protected your private key.

How does it fail to prevent this? If you are the custodian of your own digital wallet (vs a PayPal account or linked bank account), PayPal cannot just remove money; it's not technically possible. All transactions are user-initiated.

It's fine to dislike crypto, there are valid reasons, but let's be factual here.