Yes, so all in all for satellite vs. fiber in backbone applications, I'd say that it's a wash (or slight win for fiber) when it comes to security, and a definitive win for fiber when it comes to jamming resistance.
In the field it's a completely different story, of course – you can't always pull fiber (although it does appear in unexpected scenarios, such as fiber-operated UAVs or torpedoes).
Not sure. Jamming a wireless signal is an active process that stops interfering when you stop transmitting.
Destroying fiber with a backhoe or an axe doesn't stop interfering when you stop digging or chopping though.
Wire-guided drones and missiles seem to be increasingly common, probably due to the cost of instantaneous radio jamming being so low - that's a short-lived signal that is going to a vehicle near your adversary. Torpedoes make a lot of sense for other reasons because radio has a very hard time getting through water (and things like sonar have too low bandwidth as well as giving away your position).
However, it's very easy to cut a fiber in a way that is hard to repair. Fishing trawlers do this all the time. In that sense, fiber can be "jammed" (sabotaged) much more easily than radio/satellite.