It's an in game glitch, and i'm assuming this was gonna be an attempt at abusing it for 2x the dirt each time. No other reason why i'd think you need to hoe it.
Not being able to hoe coarse dirt is not a glitch. It's a plugin mechanic. Dirt is a somewhat rare item, and "legally" duplicating it would ruin the market.
I don't know why you assumed that I would be abusing it... I was just reading up on the new items since I have only just got back into Minecraft, and I read about how coarse dirt can be turned into dirt, so I wanted to give it a try. I spoke to a mod about this and they told me to post it in the bug reports forum, as I mentioned in the post (they didn't say anything about it being there to stop getting x2 the dirt). At the time I didn't see how it would abuse anything but since reading your reply I can also see how that can be sort of 'game breaking' for the skyblock market. Sorry for the essay, but I just wanted to get my point across, I'm doing everying legit xP.