Because men 18-35 had to serve for 3yrs, later 17-50, and if he couldn't afford it, he would have to hire a substitute to serve for him.
People could only recognize and worship only 1 god. Hope I helped :)
In order to truly understand an event - whether personal or historical - it is necessary to look at it from multiple perspectives.
Just like you cannot understand history from just one book, you need to ask multiple persons to help you with your personal event.
