BigTen Protected Opponents - PSU has none?

Protected Rivals starting in 2024:

Teams with 3
Iowa: Minnesota, Nebraska, and Wisconsin

Teams with 2
Illinois: Northwestern and Purdue
Michigan: Michigan State and Ohio State
Minnesota: Iowa and Wisconsin
Purdue: Illinois and Indiana
Wisconsin: Iowa and Minnesota

Teams with 1
Indiana: Purdue
Maryland: Rutgers
Michigan State: Michigan
Nebraska: Iowa
Northwestern: Illinois
Ohio State: Michigan
Rutgers: Maryland
UCLA: USC
USC: UCLA

Teams with 0
Penn State

How on earth did Penn State get away with zero protected rivalries? OSU vs PSU has been a great match up the past decade or so.  Seems like it lets both OSU and especially PSU off the hook.

I get the PSU vs MSU rivalry never really took hold well, but OSU and PSU seems like a legit rivalry and gets big TV viewership year after year after year.

Is it fair to Iowa that they have 3 rivalries to get up for while PSU might have none in a year?