They could have easily crammed the Steam Deck full of stuff to make it hard to use for piracy - locking down everything, making it usable only to play games you legitimately own, force you to go through who knows what hoops in order to play games on it. That’s what Nintendo or Apple or most other companies do.
Doing the absolute bare minimum to not be consumer hostile does not warrant praise. Just because Nintendo or Apple are worse doesn’t mean Valve is heroic for not doing things they really shouldn’t have the right to do anyway.