Hi, Mohammed!
I can understand your disappointment, but you should realize that civilians are completely on their own, that's their specifics. Everyone is potential threat for them, they got no friends and the eternal struggle is their perpetual destiny. There are no 'protecting' or 'attacking' civillians: they are just civillians. No wonder cops and security shoot you on sight: they don't want to risk presidents' life by letting you reach him. So, as it has already been stated, choose any other class if you want more certain duty.
Yeah, there is a problem that cops and security are hardly availiable, but afair there were a few patches just to fix this issue, so it must be more or less fine for now. Besides, you can consider
joining our VIPs community, and, among other benefits, you will be able to choose any class but president and vice president anytime. That's it.