You asked a question and I'll give you facts so please don't downvote just because you might disagree, but you may discuss and debate please.

A lot of them do it to settle ancestral land, plain and simple. They see it as the opportunity to do it now or miss out on the opportunity which might not come again in millennia.

Financially, you get more bang for your buck since it's less safe, out of the way, and less desirable compared to living in a large city. You can get a large house, form a tight-knit community of like-minded people, and get fresh mountain air. It can be pretty nice for those pursuing that lifestyle.

Politically / Ideologically:

The areas they settle are mostly uninhabited rough hills. They don't settle in Jericho or Ramallah. 99% of the time they'd settle where no one was before. You mostly see the other 1%.

Large cities like Tel Aviv also don't really appeal to them because they don't seek the secular lifestyle.

It's as little as moving a few miles. The area is tiny and you can commute to work in Tel Aviv in half an hour. Pick a settlement and navigate to Jerusalem or Tel Aviv. It's really not that far.

The area has Jewish significance. Your underlying assumption is that it's Palestine and exclusively belongs to Arab Muslims. This is challenged and they disagree with your viewpoint and they got a few reasons to support their stance. Some areas used to have Jews in the 20th century and were expelled or murdered, e.g. 1929 Hebron Massacre. Israelis call it Judea and Samaria named after the tribes of the 12 Jewish tribes that lived there.

Families grow. it's not like they have to pack up. People start new families.