"but is it frowned upon if you bring noise-cancelling headphones"
Yes, at (former, thankfully) employer its the border between actionable offense (being written up) and merely being viciously trashed at review time. Management made the explicit decision to enforce collaboration (a 'la the whippings will continue until morale improves) and your actions are direct and intentional insubordination of that explicit formal requirement.
One person will get yelled at in front of everyone else (because its open office, duh) and nobody will dare to wear headphones again.
Its hard to find a more open and shut case description of intentional willful trivially documentable insubordination.