I see no problem with a canned soda or a cup of coffee... or a evening cookie.

I have sometimes taken breakfast back to my room, if I was working in the room in the morning.

What is the harm done?

As some have pointed out, sometimes the lounge is just too crowded to find a place to sit.

And, I have seen lounges that were not appealing places to sit and eat, due to folks who have come from the room in their bathrobes, or from the exercise room in their sweaty workout clothes.

So, I think there is no single good answer... whatever the context dictates... as long as the guest is not seeking to abuse the policy.