it doesn't matter what the tangible, corporeal or incorporeal entity is, what matters is that it is one and that it is scarce.
Your gut feeling tells you that bitcoins are valuable because only 21 million will ever exist, what you are missing is that those bitcoins have to exist as records in
the blockchain database we all use, otherwise it has no value.
Ownership of bitcoins means you are free to change the record by sending it to anywhere.
Stealing of bitcoins means unauthorized change of the record by sending it to an address controlled by someone else.
How I define ownership and property the above makes no sense. Perhaps you should start by defining ownership and property before you draw conclusions.
That's exactly what I did:
Property: a record in a database that is consistent among many people.
Ownership of the record: ability to rightfully change it.
Stealing of the record: unauthorized change.
If that makes no sense to you then there isn't much I can do about it.