Are people who kill themselves less dead than people who are killed by others. Because, frankly, my neighbor who shot himself, he looked pretty dead to me at his funeral. (Although the undertaker did a nice job patching up the hole...)
The reason it should not be included is that when usually stated, it is made to imply someone being accidentally shot, the classic "I shot my son by the fridge because i thought he was a burglar" story. The people who often use this study use it to make it appear you are going to shoot your cousin ed well before you shoot an intruder. Using suicides to bolster the ratio is intellectually dishonest if you intend to use the numbers this way.
Basically, the study billed itself as proof that "Guns in the home INCREASE danger". But it's been proven conclusively that the presence of a gun does not increase the danger from suicide whatsoever, and they are actually MORE likely in places where there are no legally-owned guns. Therefore, since suicides have no relation to the point the study is allegedly "proving", they have no business being included in the study.
Sure they can increase danger. And a lot.
But that has nothing to do with responsible gun owners.
I advise all my clients to NOT keep your weapon loaded unless it is under lock.
Safety is a responsibility of the owner, not the government to mandate.