I spoke with a Reform Rabbi whom I happened upon in a kibbutz and he told me that matrilineality, being Jewish by virtue of the mother being Jewish, has only been practiced since the Babylonian times and for reasons I haven’t quite understood. (something like: the Jewish men could be separated during the Exile and killed, so Judaism might survive through the women kept as slaves: I might be way off though)
I found it difficult to find varying and accurate sources, I understand Orthodox Jews believe matrilineality had always been the case (since Mt Sinai) and that Conservatives believe the practice to have been adopted much later.
What do my fellow redditors know or think about it?
I welcome elaborated answers, although I think I’d find it easier with a vulgarized ELI5 as I’m afraid I’m not familiar with the intricacies of Talmudic teachings.