I find there are those who are simply uneducated / naive, and after explanation (and example) they sound interested, or at least drop suspicion.
Then, there are those who are uneducated, lazy, and want everything spoon-fed to them (sadly, this is the majority). Furthermore, they tend to be the ones who don't want to work hard for it anyway. They are the types who buy into the "15-minute abs" type crap they see on late-night infomercials, or whatever the hot gimmick of the moment is. These are also the types who attribute ALL good physiques, not just IFBB Pro's, to steroid use. Yeah, b/c steroids mean you don't have to work hard, eat right and remain on track? Bull$h1t!
Haters are everywhere. F--k 'em! Do what you want for your body / life. Most people have no grounds to insult you for your choices, anyway. It is typically just jealousy.