Nobody's talking about bows. That's a lot different than a crossbow. And a crossbow is a lot easier to use than a gun - I've used both and trust me, having no kick to your weapon really makes it aim-and-shoot.
Who do you think winds up the siege crossbows when there are few creatures bigger than Parson around that have hands? All siege crossbows would be meant to be operated by the inhabitants (therefore a creature smaller than Parson can load it, winch or no), therefore Parson will be able to load it.
Regardless, Parson doesn't have the raving badass image required to run around with a siege crossbow.