I feel Speedhide is one of the most underrated primer/sealers for new drywall
Please keep in mind I'm usually brush'n'rolling it as part of an occupied remod, but I find it's coverage, sealing, hiding, adhesion, and finish, as a "commercial/builder's grade" to be excellent for the price and good enough for premium jobs and I do not hesitate to use it as such when it's appropriate or convenient
I wouldn't use it for many other apps, but new drywall I find it excellent
The guy really, really, shouldn't have put floetrol in it
I can't imagine why anyone would do that
Short of viscosity for spraying specific reasons, you really shouldn't be conditioning primers anyway
Sounds like a "the guy at Home Depot said...." type tip
'cept I know he didn't get the Pitts at HD...lol....