The hack that's called "Sonic 2D Blast: Westside Island" is just a hack of Sonic 2 and not a game itself. Besides, that hack isn't even that much Sonic 3D Blast as it's just still using original Sonic 2 stuff like the music for example. So it's ok to call this "Sonic 2D Blast" because Sonic 3D in 2D is much more 'Sonic 2D Blast' looking than the rom hack of Sonic 2 that uses that name. However, it's possible that you and other people didn't want to think about this awful game called "Sonic Blast" which does happens to be a 2D Sonic game that contains the name "Blast" in it.