To me, it is worded to imply PGProduct(s) were required, but really doesn't say that.
It says -
"users of PG Music products (e.g. Band-in-a-Box or RealBand) can post links to their original song compositions, for others to listen to"

Qualification 1: I use PG Music products
Qualification 2: I can post a link to an original composition

It does not say the two have to be combined. It could have easily been worded to require it, but wasn't. Instead it was worded to imply it.
If this was done with forethought, I'm fine with that.

I do not work here, but the benefits are still awesome
Make your sound your own!