These discussions tend to get a bit heated...take a look at some real ballistics data though and you see the two weapons are in fact very similar

Outdoor life reported...

"...It turns out that, from a ballistics perspective, crossbows aren’t that different from modern compound bows. Consider a middle-of-the-road crossbow (175-pound draw, 420-grain bolt pushing a 125-grain field tip) and a moderate compound (75-pound draw, 350-grain shaft tipped with a 125-grain field point).

Based on the bows described, the crossbow generates significantly more energy at the bow, about 115 foot-pounds compared to about 82 foot-pounds for the compound. Shaft velocity is comparable, at about 350 feet per second measured at the bow.

At 10 yards, both shafts will drop about 1 inch. At 20 yards, both drop about 6 inches. And at 30 yards, the distance at which most deer are shot by bowhunters, the compound shaft drops about 17 inches from its zero; the crossbow bolt drops about 15 inches. At 40 yards, the compound drops about 30 inches, the crossbow about 26 inches."