Some may be critical of a real Christian who states that Israel has rejected the real Messiah (Jesus Christ), and that, to get along, should not bring this up as a thorny topic.

In Matthew 23, Jesus releases a diatribe against the spiritual leaders of Israel (Scribes and Pharisees), who have led the people away from God.  This chapter ends with the following 7 verses which are spoken by Jesus:

{23:33} [Ye] serpents, [ye] generation of vipers, how can ye escape the damnation of hell?
{23:34} Wherefore, behold, I send unto you prophets, and wise men,
and scribes: and [some] of them ye shall kill and crucify; and [some]
of them shall ye scourge in your synagogues, and persecute [them] from
city to city:
{23:35} That upon you may come all the righteous blood shed upon the earth, from the blood of righteous Abel unto the blood of Zacharias son of Barachias, whom ye slew between the temple and the altar.
{23:36} Verily I say unto you, All these things shall come upon this generation.
{23:37} O Jerusalem, Jerusalem, [thou] that killest the prophets, and stonest them which are sent unto thee, how often would I have  gathered thy children together, even as a hen gathereth her chickens under [her] wings, and ye would not!
{23:38} Behold, your house is left unto you desolate.
{23:39} For I say unto you, Ye shall not see me henceforth, till ye shall say, Blessed [is] he that cometh in the name of the Lord.

Israel will one day recognize their Messiah, Jesus Christ, and be saved.