As Christians, is it biblical to have to support Israel and its politics? Abraham is also the father of the Arabs also right?
You appear to be making a statement rather than asking a question.
The answer is no. A Christian always has free choice. You can actually pick and chose what parts of the bible you believe and reject all the rest. Many Christians do just that.
I do not support all the actions of the nation of Israel nor do I support any particular "politics". I also do not support all the actions of the United States nor do I support all the actions of the Democrats or of the Republicans. I do support the United States as as a sovereign nation and work within that framework to bring about the policies I believe are best. This is not the issue.
The issue is prayer for the People Israel. We recognize the absolute connection between God's chosen people, incorrectly called Jews; and the people who recognize Jesus Christ as Lord and Savior, the gentile church. The fate of both groups is dependent one upon the other. For gentiles, salvation comes from the Jews. For Jews, salvation comes at the end of the age of the gentiles. The People Israel are all people redeemed by God. We pray for ourselves.
And just a side note, "Arabs" as you use the term are gentiles. As such they have, since Abraham, been able to convert to Judaism. They can also, like all other gentiles, claim redemption through the blood of Yeshua and join God's people though the gentile church.
Reject the policies of Israel as you think best. Reject God's people at your peril.