for a long time the private key '0000000000000000000000000000000000000000000000000000000000000000'
had lots of btc, but I notice now its gone, you used to not be able to use that address, so they patched the code enabled and somebody swept the address
That private key is invalid, has no associated public key, and therefore has no associated address. What address are you looking at that you think has been swept?
This address is also a 'burn', as there is an hash160 of all zeros, or if there was it would take an infinite amount of time to find that hash that only contained zero's.
Even if someone found a hash collision for this address (or any address, for that matter), the would only obtain that address's public key, and would still have to solve the ECDLP to find the private key.
Your missing the point, that address for private key all zeros, used to be an invalid address, while 'ku' can't generate the address you can by using ecdsa algos yourself, I noticed last year that the address now had a zero balance, so somebody modified bitcoin internals to accept that addresss, now the only address that still has a balance is hash160 all zero bitcoin-address.