The point of crossbows has always been a weapon that can be used with minimal training.
But they still require a training. Saying that a crossbow can be used by everyone is like saying today everyone can use a gun or a rifle without or with a minimal training, this is true and false at the same time.
Yes you can use it without training but only if you want to make a shoot above 25m (and with some luck). Try to make a shoot at 90/100m and see how your shoot gonna fail.
If we keep your idea, everyone can also take a bow and make a 10/20m shoot without training. Or everyone can take a sword and can kill someone. If we follow what you say, we can remove all the requirement already in game because they have no sense.
Requirements are not here for realism, they are here for the gameplay and for the game balance.
If you want to talk about realism, we can discuss about the bolt who stay loaded when you have your xbow on back (the bolt should drop on ground, xbow didn't have attach for loaded bolts) or we can talk about the real reloading speed because historically, a good xbower can make, in good condition, 4 or 5 shoots per minutes (and when I say a good xbower, I mean a good trained one, see wikipedia for references)...