They do
Compaired to say.. Someone working in medbay, you will win a hand to hand fight easily because of the standar security armor which reduces damage taken to you.
We can't "up" the health of security officers alone, mainly because of how the coding works, so the only thing we can change is the armor values and how armor works.
Right now, as the HoS you are able to take about twice the amount of brute/burn damage because of your armor, don't let the "coat" fool you, it has huge armor values, the Dermal armor patch even more so.
As for the mini crossbow, yeah stun in this game is OP, but the crossbow is also a dead giveaway and HAS TO be used 1v1, or else you'll risk someone exposing you and, well then you're fucked anyways.
This game isn't all "well i am security I am god"
Yeah you'll probably loose versus a sec officer because you do not have stun gear as a normal Civilian (assistant) and he'll fuck you up good, thats why you need to find better ways to take them out