Respectfully disagree, and quite adamantly.
Rutgers is an Internet message board rival, true. They are decidedly not an on-the-field, most-of-the-fanbase-cares rival.
Sadly, SU doesn't really have a rival in football. If you squint you can try to convince yourself that our rivals are BC and Pitt. I guess they are, although there's so little heat there, I'd say that they're better categorized as "longtime traditional opponents" than "rivals". But that may be semantics.
I'd argue WVU was our last real rival, and that died with the Big East football conference.