Crypto currency is considered property by the United States Federal Government. Taking or destroying someone else's property is a criminal act.
I am well aware that forking to remove coins can and has been done, but this does not make it legal or morally right.
It is considered "property" only in a very limited way - for tax purposes. That does not mean that you could maintain a claim for conversion or theft if your coins were blacklisted.
If someone broke into your wallet and transferred your XPY, **that** would be conversion. if you sell your XPY for a loss or profit, the IRS will require you to recognize the sale as income or loss. All true.
Blacklisting a coin in a forked blockchain is not the same thing. You still have your wallet, still have your coins. Its just that no one is supporting that old blockchain anymore so the XPY you have in the old wallet becomes worthless.
You would have to somehow argue that U.S. law would protect not just the coins as property, but also your interest in continuing to be able to use the coins on any blockchain. I don't see how this argument could be made.
Forget morally/ethically/legally right or wrong.
Why would you/anyone participate/hold/use/invest/develop in a coin if this is done. It can be done to bitcoins, but bitcoin works because it's so hard that it's almost impossible to do. Why would you bother wasting any time/energy/money on a coin that has shown can be taken away like that? It just doesn't make sense It can be done, but doing it should kill the coin so why do it?
I mean this saga (and crypto, in general imo) is full of people that suck at logic and common sense, but wouldn't this be a bridge too far? Forget the morality of the fork, look at the reality that will happen in the aftermath. A coin that has shown that it can easily be taken/blacklisted if you piss off a group of people that are either morally corrupt or incompetent to be involved in this mess up to this point. Doesn't seem like a smart idea to me.