Because Jehovah as He has done in time past will take rebellious and stiff-necked Israel and through chastisement will bring them to Christ. They will look upon Him whom they have pierced and mourn. The tribulation will be upon Israel to bring them back to God. The whole world will be involved but it is Israel that will receive correction and will see their Messiah descending from the clouds and recognize Him and be saved.
As the Gentile church we need to get over ourselves. Israel will be blessed and we will rejoice in Jehovah blessing them
I am in a church which is neither Jew nor Gentile (Gal 3.28). I have been made one with all ex-jewish and ex-gentile believers in the church of God. As with Israelites who believe. We are no longer strangers and sojourners but have all become fellow citizens with the saints and of the household of God. (eph 2.11-22).
If not you may not be part of the church. Self examination time you know.