What makes you think Purolator did, or did not, make this? I agree on principal; it was made by them, of for them, to some spec that was satisfactory to the OEM customer.
Off topic -
Threaded stud on the filter? Perhaps an Audi application?
Just another way to take a $5 filter and turn it into a proprietary $25 filter ... Likely no performance difference compared to a typical shelf filter, but the very limited applicability makes for a very captive audience!
I know because my buddy just got a new little Audi SUV and he was SHOCKED when he realized his filter is like this one ($$$$) and he has to run a very expensive syn (Probably going to be M1 0w-40 during warranty for compliance).
Caveot emptor.