A major difference here is that during WW2 the rockets were unguided and fully relied on fuel-weight calculations. These ballistic missiles are GPS guided and don’t suffer from all of the unknown factors.
There is certainly a case to be made for secrecy, though it’s more likely they don’t want to let Iran know whether F35’s, tanks or other military equipment were hit. Israel already claimed they “intercepted the majority of projectiles” but the videos don’t really corroborate that. Similar to the Hamas “limited ground operation” last year israel tries to hide all evidence and then crafts their own story of what happened.
They most certainly can be guided. Ballistic means that the terminal phase of flight is not propelled, eg they are just falling and no longer accelerating.
Guidance can be inertial, magnetic, radar, GPS, or even star-map for ICBMs, or a combination of many of these. Minuteman missiles still rely on the position of some stars to orient themselves in exosphere coast phase. Part of their flight may be unguided, namely 3rd stage ascent where they are spin-stabilized, and during reentry phase where atmospheric plasma makes GPS guidance impossible and inertial might be inaccurate.
