@Derp
It's ... not really an assumption when the staff says that's the reason for it?
I suspect that's just an issue of miscommunication, and she was using ST in a way to mean staffing in general. Non-storytelling workload is still workload.
I'm not sure that I agree with your sentiment there. Anyone can create as much work as anyone else. Simply believing that the full-on supernatural characters are going to be the most active and involved is reaching.
You're free to disagree as you like, but it's always been true, and it's unlikely the recent changes will make it any less true. The things Mortals and Mortal+ types require staff support for are very rarely as involved, rules intensive, or contentious as full template supernaturals. The simplest way to put it is that the more moving parts something has, the more options that exist, the more ways it's going to be a pain in your ass. Werewolves have whole suites of stuff they can do, how they interact with the world, that are unavailable to Wolfblooded. Same with Ghouls and Vampires, etc.
A Vampire has all the same stats as a Ghoul and Disciplines and specific stat-linked social groups, all of which adds up to the average Vampire player generating more work over time than the average Ghoul player. Werewolves even moreso since they have an entire subset of shit that inevitably requires staff adjudication in the form of spirits, Fetishes, the effects of Rites, etc.
That's not to say any given non-major template person can't create the same volume of work for staff without any of that, but that's by far an exception, not the rule.