Why wouldn't they want the .com? I can see how just owning the .ie would be understandable as perhaps the .ie is used more then the .com over there. But then...registering .net and .org? Surely the .com has to be stronger then the .net or .org over there, even if the .ie is number one.
BTW, the .com was previously registered, before they registered the .ie, .net, or .org . They use to just go under just another domain (in which the own the .net and .org extensions too), but they went ahead with these ones too.