If they are alphabetical it's missing a bunch since it shows GMP first. Strange.
We decided against alphabetical since it could only work for English and result in a meaningless order for any other language, and because that would be harder to manage when we added new supports in future and had to rearrange the list. So instead we chose the order of their being added to the game (and I went on a fun dive into the far past to determine which was the first support effect added). This way future supports can be added to the end of the table without disrupting any existing ones, and it's a neat trivia thing that GMP (then "Multiple Shots") was the first support in PoE.