Something has always bugged me about firearms and I thought I would pose it to this board, especially since the predominant round being discussed is the sissy 5.56...

(please read sarcasm into that statement).
I grew up shooting a 30.30 and a .270 my entire life. I have watched amazing kill shots happen with the .270. Of course I shot plenty of 30.06 and other calibers too, but where I came from these were the only real man calibers for anything: 30.06, 308, 45 Colt. Everything else was pansy unless it was a magnum.
I still come up against this. Certain people railing against my AR because it's 5.56, or that my deer rifle is a 30.30.
What the hell is the origin of this machismo? Any thoughts? Also what are some of the other calibers you watch get made fun of, that you know are perfectly capable of doing their job?