Originally posted by Knight Templar
No it's not.
Go watch SG-1. They don't have lasers and explosives and trip-mines and machine guns mounted on the gate. They have the iris, which effectively closes the door and locks it. If that's not enough, or they want more security, they have soldiers with guns come in.
I recall several episodes where they had missile launchers pointed at the gate, ready to fire, as well, but it's still a faulty example.
We are, after all, talking about a giant, manned, space-based construct. The proper analogy here wouldn't be a door, but rather something like a narrow straight. That matches both the scale and the usage of a Knossos much more closely.
They already have crew onboard, which will require some kind of defenses. Otherwise the crew is not going to work on the thing. Stationing ships there permanently to defend it is a waste, both tactically and logistically. A seperate defense platform is also logistically wasteful. Post-Capella, the GTVA can't afford that waste.
By contrast, having the gate able to defend itself increases the tactical problems a force trying to seize it faces. They have to somehow deal with those weapons, without damaging the gate enough to render it non-functional. It decreases logistics problems, as all the parts and supplies are going to just one place. It obviates the need to place a destroyer on permanent guard duty, a waste of the offensive, and much of the defensive, potentional of a destroyer.