I wouldn't say that's necessarily true. Definitely some believe that, but I think the majority opinion was the idea that Jews needed Israel as their homeland to protect them from persecution in others. The belief that we don't belong outside of Israel may just stem from a leap too far with the above idea.
But considering the hardships of the 18th, 19th, and 20th century, I can very much see why someone would think that.
Not all nationalism is created the same, nor exclusive to one idea. There can very easily be Zionists who believe what civ_king is saying, and considering what some Zionists believe, it definitely isn't out of the realm of possibility.
Then what's the issue here? If you willingly choosing Israeli citizenship, then you are responsible for all the ramifications of that choice. If you can choose not to join the crappy mandatory military service system, but you choose to do so anyway, then there's no ground for your objection to certain aspects of that crappy system.
Aye, they are. Considering their fervor (and the fervor to support them here in America), I don't think they'd have much issue getting volunteers for their military.