Is it true if that were to happen, all I need is the private key to spend the funds?
Private keys are the means by which transactions are signed from corresponding addresses on the blockchain which were generated from they xpriv key. So, with the private keys you will be able to spend funds from that address.
If it were possible to generate private keys and public keys which has a balance on it, then it would not have been worth it, as the network would haveko value.
Of course, the network isnt as fragile or hackable as some people think and if anyone could
achieve what the OP proposes the
BTC they steal would be worthless.
If I wrote a computer program that generates private btc addresses and then generated the public address, if that public address has a balance, and if I then imported that private address into a wallet, could I claim the money on that wallet?
You don't need a special program to generate private and public keys, any bitcoin wallet can do the trick. The odds of you accidentally finding a private key with a balance are extremely slim, but no one can stop you from trying. However, keep in mind that stealing someone else's coins is to be considered a crime in most jurisdictions.
Erm I dont get how someone would publicaly ask how to steal someone elses property?
and think its ok.
Obviously the OP has given it plenty of thought as have others, if you have the knowledge
why not use that to benefit the community?