In The Good Man (S01E06)
where the characters leave their walled off community I don't see them closing the gate.
Is there a reason why they wouldn't do this?
They don't have any beef with any of the residents as far as we see in the show.
The controls had to be on both the inside and the outside because if they weren't, the military could not have closed the door behind them, as they appeared to have done.
Knowing what they intended to do would leave a catastrophic number of the Walking Dead everywhere, you figure they might have taken the time to tidy up behind themselves and give others at least a fighting chance with the gates all around them.
The only reason I can see for not doing it is if they thought there wouldn't be any power afterward, this would mean it couldn't be opened or closed after the power went out.
I want to give them the benefit of the doubt that there was a reason, because otherwise I have to assume they are just careless and unconcerned about the welfare of others.
Which I found odd since they took the time to free prisoners when they went to the hospital. Perhaps it was a plot hole no one thought to fill...
The only reason I can think of is this: they left the gate open so that they would be able to return later.
It makes sense that the military would design a gate that cannot be opened from the outside, right? I suppose Travis could have flipped the close switch and ran back through before the gate closed, but then (if the military is as smart as I think they are) the survivors would have a harder time getting back home. Yeah, they have bold cutters, but who wants to spend time snipping a fence with a zombie horde at their back?
Also, as some people have said, Travis' group doesn't really feel any responsibility to protect their neighbors. There is evidence of this when Madison sees the family as they are leaving. They are acting like the apocalypse has not happened while Madison has already seen and done some horrific things. At this point I feel like Travis' group have adopted the attitude that they have to take care of themselves first.
First off, no, we don't see anyone closing the gate, but that doesn't necessarily mean that no one did so. It might have happened after the shot ended.
Even if we assume that the gate was left open, it doesn't necessarily mean that they chose to leave it open. Consider the circumstances under which the fence was erected.
The military cleared the surrounding areas, isolated a single neighborhood, and set up their defenses there.
"Cobalt" was put in place as a last resort, in case the crisis spiraled out of control, but the military probably believed that Cobalt would never be needed.
Thus, the military built the fences and gate under the assumption that they, the army, would always be in control of the gate.
This means that they thought there would always be a guard inside the gate, waiting to let patrols in and out of the compound.
This in turn means that they probably didn't put a control panel on the outside of the gate. Whoever was on guard duty would use the interior control panel to open and close the gate.
Furthermore, it makes more sense to have a single control panel inside the compound, because the whole idea of having a compound is to keep the people outside of it out. Giving the people outside a way to get in defeats the purpose of having a gate.
If this assertion is correct, there is a simple answer to the question of why they didn't close the gate: because they couldn't. The control panel was inside, so once they left, they didn't have access to it.