Check out the Magpul UBR Stock. I have one on my AR and love it. It even came with the needed buffer tube!
Also, the stock you linked is in fact designed for an airsoft gun. It even says it in the link! (AEG = Automatic Electric Gun)
I see no reason a PTS (which is magpuls airsoft brand) stock wouldn't work as long as it's milspec or commercial per your needs. As to whether it would break if dropped or wiggle is another story. I'm considering buying PTS gear to set up a .22 ar and doing a review on the differences.
Id love to see a review. Ive just always wondered about how much difference there was.
I'd be worried about the tolerances. Sure, with a .22, you're not dealing with a ton of recoil so it might be fine. Anything larger, and you're putting a LOT of extra stress on something not designed to handle that much. Thus why there is the price difference. If Magpul could sell the same stock for airsoft and real steal at the airsoft price, why wouldn't they?
I would never use airsoft products on a build that I would need to rely on. More for the same reasons goodcat has stated. A cheaper .22 build that would only be for plinking and looking cool.
I just don't want people on here to think it would be fine to put an airsoft stock on a .50 BMG or other large caliber!