Jordan is not the only one but in general there's usually only a few reasons as to why hot guys online (the straight ones in particular), don't want to show their real dick, even when showing off their bodies in a sexual way.
They just care way too much about what other people "might" think. Even if the guy is well hung, soft or hard, and has nothing to be ashamed of. But if someone is a fan of you then they won't care what you look like down there.
But as far as these guys online who play around with photoshopping their photos, enlarge their videos to make it look bigger, and use dildos, I think it really boils down to being too insecure about the situation. It's all just beyond ridiculous.