First, Michonne had those walkers for a long time and she still carried a weapon as it was not 100% effective. According to that logic two walkers would be needed per person and that would be a lot of walkers to keep track of. Second, they cannot carry gear for very long as they decompose over time. Third, as far as accuracy with handguns, I think you are grossly overstating the distance as I have yet to see anyone shoot anything with a handgun at even 150 yards (unless you have no idea how far that actually is). Fourth, for peoples knowledge of weapons, you do realise that time is different on the show. Even though you saw someone last week or two weeks ago not know something, when we come back time has passed.
Also, you say that they dodge bullets with ease and also that they miss with weapons at a distance. So, which is it? Are they really good at dodging or are people not as good of a shot as you say they are? Fifth they are trying their very best to keep what little humanity they have left and being covered in guts day after day, may make some people crack. Hell, there are cannibals on the show and it would be real easy to go down that path to survive but, Rick and the others choose to be better than that and find other ways to survive. Sixth, the prison attracted walkers as they made noise in the prison, did not mind being seen by the walkers (protected by the fence), and the smells of people, animals, and food cooking would attract them. Remember, it is a herd mentality with walkers and when one does something, others will follow. Go into a public place and start looking up or down like you are trying to find something, eventually people around you will start to do the same thing without any vocal cues.
One last thing, in the end it is a TV show and will not be perfect.
