Jesus: the first Socialist &/ the ultimate King?

My French teacher declared that St Peter was crucified upside down because the Christian church was a threat to the hierarchy in society, being such a mix of all classes and treating everyone as equal. After all, she said, Christ was the first socialist (declaring all people equal).

She's knowledgeable, and being in the class is a delight in getting to discuss things of interest, but also oppressing whenever she declares something about Roman Catholicism or tradition as if it's Christianity. I interjected (in class discussion after all we're encouraged to) that it was only myth that he was crucified upside down in Rome, but anyway, from reading the New Testament it seems that persecution of Christians had less to do with equality of persons and more to do with refusal to treat the emperor as God and insisting that Jesus was God, and explosively using the titles of universal Saviour and Lord for Jesus rather than the emperor being Saviour and Lord. She agreed and we moved on. But it distresses me when it's dismissed as 'interesting cultural background' (like Greek mythology, which also came up) rather than living truth. For a more explicit example: we were discussing how in French, 'Christian' festivals get capital letters, but other festivals don't, and she declared that after all, this was in the time before 'Libre pensée' - Free Thinking. She said this in a way that said not only 'there wasn't equality between religions', but 'of course now we know better'. But it does potentially give opportunities to speak. Please pray that I'd have wisdom and clarity in using them as well as speaking with mind to Jesus as Lord in general class discussion.