I'm not accusing you of ignorance - An argument from ignorance (i.e. argumentum ad ignorantiam) is the name of a known fallacy, which you're making with your claims: https://en.wikipedia.org/wiki/Argument_from_ignorance
You're engaged in the fallacy known as "straw-man", where you argue against a point I'm not making. I'm going to state my argument clearly so you can't continue to weasel around it.
The technical properties of bitcoin can be modified, saying that it is impossible to change them is wrong.
This is part of the argument from ignorance - the attempt to push a burden of proof when the claim you made was "Unforeseen future circumstances could make people more amenable to any kind of changes imaginable". I didn't say anything about impossibilities, maybe you're confusing me for someone else?
The technical properties of bitcoin can be modified, saying that it is impossible to change them is wrong.