The fact that rapes are declining statistically is not actually a consolation if you happen to be an actual rape victim. If it makes it less likely that you'll believed, it can potentially hurt you.
It's really hard to call it a 'moral panic.' Moral panics are urban legends like razor blades in halloween candy, aka things that never actually happened.
Plenty of rapes are actually happening on campuses. Campus rape is not an urban legend. Whether it's 1 in 5 girls or 1 in 20 girls, it's still a high occurrence of a very serious crime with very serious, potentially life-long trauma implications.