Israel is not "God's chosen people." True enough.
Holidays come from manmade religions, referred to as "pagan." All true.
They don't believe in fighting wars for political agendas, at least not those of the nations. Yes.
On those points, they do seem to heap praise on ancient Israel as God's chosen people. That way, they can claim they are modeled on God's people, and therefore are God's people. That is their self serving part- saying "No, WE are God's people."
Avoiding holidays with pagan roots is more about isolating themselves from 'the world.' They put an unhealthy fear in children to avoid birthdays and any holiday stuff. If Christmas offends you, don't do Christmas. Same with the rest. But does a child have to fear that he let God down because he wanted a birthday cupcake from a worldly classmate?
JW's are fighting a war against the world and are dying, letting their kids die, for the agenda of Watchtower with the silly blood doctrine, and keeping their flocks ignorant with their view of higher education.
They do not know the Bible so great as others have mentioned. They know snippets that support Watchtower doctrine. I could go on, but you will know this when you pay attention, and read the good points made by others here.
The sometimes-figurative, sometimes literal use of the Bible is all based on what the men running Watchtower want the people to think, do, believe. Whatever keeps them in line best.