The film script offers the following information
INT. STAR DESTROYER HANGAR - NIGHT
Poe, shackled, is ushered from the transport through the hangar. He is
awed by the imposing space.
POE: All right. All right!
The film's official novelisation concurs, stating that it's "enormous and impressive".
The shackles that Poe had worn on the troop transport were removed as soon as he and his captors disembarked. Aboard the Star Destroyer, there was no reason to physically restrain the prisoner. Apparently enjoying themselves, or perhaps merely impatient to get out of their armor, his escort chivvied him along with what he considered to be unnecessary roughness. Not that stormtroopers of any ilk were noted for their individual diplomacy. Considering whom he had tried to shoot, he knew he ought to consider himself fortunate that they had brought him aboard still attached to all his important appendages.
A physical state of being, he knew, that could be altered at any moment.
On the other side of the enormous and impressive receiving bay, other troopers were filing out, grateful that more of their number had not been lost on the expedition and looking forward to some rest and food.
You may wish to note that this Star Destroyer is nearly twice the size of a standard Imperial Star Destroyer and the receiving bay is apparently similarly scaled upward. Even if Poe was familiar with Star Destroyers, the Finalizer is simply bigger and more impressive.