Why are certain members of the Jewish community conservative?
We need both conservative and progressive values. They aren’t opposites—you can be both at once.
The world is in constant flux and it is important to be amenable and adaptable to improvements and changes. At the same time there needs to be a balanced and well thought-out consensus so that a radical minority does not lead us over a cliff, ala Pol Pot.
The Jews—they are us.
because some people believe in "me/mine" first (conservatives) while others can consider "we" first (progressives).
Because the Jewish people, like every other culture on Earth, is made up of ... people. I grant you that each group will reflect its cultural history and experience. In general, the Jewish culture is not much different from others when it comes to ideas, ideals, and social interaction. An entire spectrum will be found, should one take a sufficiently broad sampling of the culture. Extreme liberal leaning. Extreme conservative leaning. And everything in between. Every curve of every culture will be skewed one way or the other depending upon the culture being investigated, but they will all fall within a narrow range of difference. People are ... people.
For the same reason that anyone is conservative, I imagine.
Conservatives, in general, have a rosier view of the past than do progressives. Progressives want to move toward a future that may or may not be realistic. Conservatives want to return to a past that never was.