The PCUSA denomination has a history of being far more liberal (both socially and biblically) than many other denominations, including the PCA--Presbyterian Church of America. While I agree with the poster who pointed out that the church is a private group that is free to support or do business with whomever they want, from a religious standpoint this denomination's opinions on Israel are not comparable to many other protestant denominations' opinions.
I'm a PCA member. Through the Bible teaching I've heard at my church and my own reading, I've developed a great admiration and love for Israel and the Jewish people. Israel has no greater friend than a believer in Christ who reads the Bible.