That's not true. If you only have a secret clearance then you're not supposed to read top secret material anywhere (unless you're "need to know") - home nor at work nor on the moon.
Right. As long as they use that judgement to avoid reading classified information. ;-)
> Army is taking proactive steps
As far as I understand (and please note that I'm not an expert) they have always blocked certain kinds of sites. That Guardian is added is not really surprising, but the indirect refusal to own up to it is whacky.