And blockchains are vulnerable to 51% attacks, especially small ones. In fact, someone can hack the blockchain "writer" that the white houses uses and push a fake transcript.

If the white house security can be hacked, what makes you think the hackers can't just hack the wallets/tools that the white house uses to push the transcript to blockchains?

Even if whitehouse website got hacked, people would quickly fix it.

No so with blockchain - one compromised staffer's computer and blockchain has bad information in it, forever.