I'll take a wild guess as to why.

Because you are young.

Most people working for government you know are also young. So you hear about the crazy amount of work they do. But here is the thing: they have to work this much because old government employees do nothing. And after 5 or 10 years busting their asses while they see lazy people not getting fired and getting their raises they'll start putting 2 and 2 together and cut back on work to focus on their family and hobbies. Or work at office politics as it is the best way to get a better pay.