Uhh... have you even looked at the huge_penis tag? There are some with absolutely ridiculous proportions, and this one doesn't even come close... Hell, this one's almost within the realm of realism... almost.

since when did the size of one's penis matter... in Danbooru?

Only going by the ToS, mate. This is ridiculously proportioned.

And unless it has its own skeleton, theres no way that things standing up by itself.

It's hilarious how this will get flagged, yet some of the more egregious stuff won't. Hell, I remember seeing a Railgun pic where someone in the comments thought Saten was getting fisted because the penis was that huge.

This really isn't that bad at all.