I complain in general about people that hoard reservations. Make what you need. Heck make a couple of extra, in case your plans change. Make 3 or 4 for the same meal? That doesn't make sense.
Just make your own. You don't need to gather whatever you see, then release them as others tell you that they need them.
And although that isn't what you say you were doing, the post indicated that you saw these and grabbed them in case someone wanted them. Sorry, that just seems pretty out there to me.
Can I stop people from doing it? Of course not. But in a couple of years when Disney charges people that cancel a reservation without a month's notice (or whatever) or they extend the time between reservations that you can make, don't complain to me. People doing stuff like this, is what will cause it. That is what happened with the $10 no show fee. People made a bunch of reservations and only went to the ones they decided that they actually wanted.