Why would this be problematic? Artist commonly work under one or more pseudonyms. 750 is quite a lot for sure, but is there material difference between that and just a few?
Hm actually I remember I read in the studio's reply to this, that there weren't 750 active artist names at the same time, this was over many years and they release under some names, then let it go and do 50 new names etc. Still.. it's some kind of diversion of the consumer's expectations. It's one thing to see a pseudonym, but in this case, it was under "normal sounding" names.
Also, the composers' names were faked as well, so there were 750 artist names and 50 composer names..