Yup! Wrong as rain. Wrong as Wrigley's. Wrong wrong wrong as the day is long. Wrong-er like a dong-er. As incorrect as the series of incomprehensible lingo I just made up. Just because a man enjoys the finer things in life (the "dirtysweats," we calls it) doesn't mean there's no room in his heart for the tender flowering of true love.
Sex is a physical activity. An awesome, mind-bogglingly enjoyable physical activity. But the same can be said for eating soft tacos or playing Boggle drunk, and neither of those things preclude me from loving my wife.
I think what you're actually picking up on is that some men, unlike some women, can and do separate their feelings of love from the physical act of sex. Sex, for many men, is something you certainly do with someone you love, but can also totes enjoy with someone who's just okay, or even a bitter enemy if she agrees not to talk during.
Sex, for a man, is not the same thing as love. And I'm not saying it is for all women, but it certainly seems to be more integrally linked. However, that does nothing to diminish a man's capacity for love. Trust me, guys can get just as stupid head-over-heels as you can, and it can make them act just as foolishly.
A man having sex with you doesn't mean he loves you. It also doesn't mean he doesn't. We can bone with or without love, or love with or without boning (although preferably with).
If your guy isn't showing you that he loves you, you should know that the culprit isn't man's innate robot-like inability to love. More likely, he's either crappy at expressing his emotions (which is certainly a man-trait), or he's just not that into you, and is sex-ing you accordingly.