* Early adopters disproportionately end up in control of majority of coins (currently 0.03% of wallets own 59% of all bitcoins)
* Proof-of-work is wasteful
* Chain is very inefficient
* Loss of coins with loss of wallet means, for one, that inheriting the coins is not possible unless special precautions are taken which undo a lot of the security
* Other libertarian nonsense that shows very naive understanding of economics that I can't think of at the moment
I would not say it is correct to call BTC deflationary. It is simply not inflationary after the final halving. Since USD is highly inflationary then BTC is "deflationary" w.r.t $1, but the supply of BTC does not shrink.
You could argue about people losing their private keys being deflationary, but that's still different from blockchains like Ethereum whose currency is literally burned in small amounts during block creations (and therefore has the chance to be truly deflationary at times).
