When I read the OPs words, I heard:
OP: "Hey, what's going on, why are we sitting here, how much long are we going to be sitting here?", etc.
FA: I've no idea.
OP: "Wow, that's efin rediculous."

I can only imagine how he'd be skewered by some in this crowd if he had said JFC or OMG.

Furthermore, having been in the aforementioned situation, I can entirely empathize. I do not have the the information I want, how can I get it? I do not have contact with the FAA, airport management, GA or flight deck. The FA is an airline employee with contact to at least one of the aforementioned, or at lease access to one who has or can get the information. Let me try asking the FA, she is the only representative of the airline and airport infrastructure to which I have access. Wow, amazing, this employee with at least indirect access to the information germane to my situation is unwilling to assist.

The FA chose not to make inquiry with the flight deck, gate (if possible?) or anything. There were so many positive choices that it boggles the mind that the situation developed the way it did. "I'm sorry, sir, I've spoken with the captain a couple of times already and the tower isn't telling her anything, we're in the dark too," comes to mind. "I don't know, nor am I doing anything to alleviate the situation," is unacceptable.

Airlines miss this oh so basic point that situational awareness often alleviates axiety, stress, etc of uncertainty. Flying MSY-PHL on US a couple weeks ago, we caught a 2 hour ground hold at PHL after boarding, before we pushed back from MSY. Captain announces the situation, permits us to deplane and the gate kept us in the loop. It sucked, quite frankly, but we knew what was going on, we could set our expectations and the spectre of uncertainty was, at least temporarily, removed.