Having them in a cap is obviously not as user-friendly as without, but the point is it will get new people who want to use the resource to download Construct, even if just to rip the stuff out of the cap and move on.
Another open resource doesn't do a whole lot because it's only a matter of time before people start saying "ah, he's using that pack" - they get old, over-used and are worth nothing other than to conceptualize. Thus, I'd want it to have people downloading Construct to use it, for secondary benefits.
Same is likely with the Game Maker people, and MMF2 people ... if someone posts a game that uses library artwork, the first couple responses point that out and tell them to make their own.