So what was the cause of Bligh's removal, and why should we commemorate it today?

a Google search on the subject rum rebellion reveals
The rebellion-en.wikipedia.org was precipitated by the Governor of New South Wales, William Bligh, who attempted to normalise trading conditions by prohibiting the use of spirits as payment for commodities. Bligh was aiming to reduce the power of the rum merchants and the New South Wales Corps, which had a role in the trade.
while this article- smh.com.au says: Proof of history's rum deal - By Michael Duffy - January 28, 2006
Another reason for the persistence of the name Rum Rebellion is that it fits with the view, attractive especially to those on the left, that the officers of the NSW Corps were corrupt businessmen. It is true many had made good profits from rum trading in the 1790s, partly because they were the only ones who could afford to buy wholesale from visiting ships. But by 1800 their monopoly had been broken by the rise of ex-convict entrepreneurs such as Simeon Lord and immigrant businessmen like Robert Campbell.
So what was the cause of Bligh's removal, and why should we commemorate it today? Essentially it was the culmination of a long-running tussle for power between government and entrepreneurs, a fight over the future and the nature of the colony.