When My Esoteric asserts that "Christianity was invevented decades after Jesus' death" if by 'Christianity' he means the organized religion of Roman Catholicism and later Protestant denominations, he has a valid point - but the ideas, the beliefs, the assertions of truth we call 'Christianity' long predates Jesus' death, and birth. The notion that Jesus was an Essene is simply not at all demonstrated by the evidence. And the idea that Jesus' divinity "was created later" is a popular notion today, but again is not at all based on any real evidence. The reason Jesus was arrested and executed was exactly because He did advance Himself to be God - that's what the Jews and the Romans of His own time, those who heard Him speak and interrogated Him, understood Him to be asserting.
Jesus did not start some new religion called 'Christianity', He proclaimed Himself of promised Messiah of the Hebrew Scripture, eventually as some Jews accepted that to be the truth and other Jews rejected that claim, and as gentiles began to believe as well, one of the terms that came to be used to distinguish believing Jews (& Gentiles) from non-believing Jews was 'Christians' . . . this was not an established and organized new church, but was the group of those who counted Jesus to be the Messiah, the ongoing faith of the Old Testament - in fact, when the word 'church' appears in the New Testament it's not referring to any manner of organized denomination, it's talking about the people, the body of believers.
As for, should Christians love Jews . . ? . . Christians do love Jews . . . and they don't hold Jews to be the reason Jesus was killed - they know Jesus gave Himself to be sacrificed for their own (Christian's own) corruption. Christians are called to love, and most particularly called to love their enemies . . . and we're also called to make no distinction between men - Jew or Gentile, male or female, Black or White, Christian or Muslim (Hindu, atheist, whatever), etc, etc, etc, makes no difference, we are to love our neighbor.