The addresses 'look' like line noise, and usually one looks a lot like another. Should they have compared carefully, especially considering the value? Sure. But errors happen.
A good workflow for high value transactions lets you preform the transaction and pass it around for validation before signing it (or after signing it but before sending it)-- but virtually no wallets enable such a workflow. So, sadly, many high value transactions are handled without meaningful review.
Other ways it could happen due to error:
Perhaps someone intended to send 26.9 BTC to "Genesis Trading" and they tasked the most unfortunate of interns to carry it out. They googled "Genesis wallet address", and the google blurb for that query gives _this address_ (I checked).
Or...
A party intended to send a test transaction to that address with a tiny amount (there are many such payments). But they are using some awful tool that makes them manually manage the payment, change, and fees amounts and they manage to pay the amount that should have been change to the destination and send the amount they intended to pay as fees. (The transaction has no change)
Or,
Imagine a backend system is pulling addresses out of a database which has them in the same order they're in the blockchain. Unlike a bitcoin node, this system indexes the genesis block so the very first address in it is this address. In that environment multiple failure modes could result in selecting this address. I don't think this one is that credible because indexing addresses by observation in the chain doesn't make a lot of sense for sending.