Valve takes a 30% cut and makes eye watering profits. I don't feel it's fair to characterize them as a victim for having to put in some effort to mention a basic standard of quality on their platform.

They've got a solid return policy, if you've played less then 2 hours they'll refund. They can probably derive a ratio to mint a hiristic and bobs your uncle.

How?

How are they a victim? People aren't going to leave Steam over this. Valve will continue making money regardless from these sales, just as they don't care that they got children addicted to gambling because it also made them money.