Not over the claim that Easter derives from a Western-European Pagan spring equinox festival. That much, I am assured by the Internet, based on one line in Bede and a poor grasp of linguistics, and a bunch of groupthink and wishful thinking, is true.
No, this disputed ground is over the existence or otherwise of a bloke called Moses.
My starting assumption is that somebody forged together a bunch of Hebrew tribes into what eventually became a big enough nation to knock the daylights out of various other tribes, and formed a nation big and coherent enough that, when it was exiled to - among other places - Babylon, it was able to coalesce around its hymns, its foundation myths and its sense of identity.
My assumption, further, is that some of those Hebrew tribes, early in their story, crossed the desert from Egypt with a certain amount of tribulation before making their home in Canaan. And that they probably had a hard time of it in Egypt, being members of a small, battered, enslaved group.
In fact, I'm going to go so far as to say that what the book of Exodus and its successors contain is the story, maybe embellished as national origin stories are, of how the nation that called itself "Israel" and became the Jewish people, formed itself - in reaction to oppression and external force. I don't necessarily believe that the whole Law Code was written in the desert - because much of that code seems to relate far better to settled life in a promised land than it does to the experience of crossing a wilderness. But, in short, I believe the story of the Exodus.
And I believe the story of the Passover. Because the Passover is the Exodus in miniature - the moment when God acted (in the sort of way, one might argue, that the kind of God who kills unfruitful fig trees acts) to let God's people go. It's the story of punishment to oppressors and freedom to captives. And it's brutal. And you may not like it. Especially if you're a firstborn. But I can get it.
And you might, if you like, posit that there was a pre-Passover festival that the Hebrews attached their nation-creation story to. Some kind of Spring festival - based on the Equinox and the phases of the moon. Certainly that's how Passover was defined. You might be right, I can't disprove it. Although it makes sense to celebrate the birth of your nation in the spring when the leaves are green. And it is a good idea to mark your religious events by the moon when you live in a world without street lights.
And then when a new group arises in that old nation, and wants to mark the death and (it claims) rising of its leader, wouldn't it make sense to attach that feast to your leader's story? The tale of two new beginnings, joined together? Obviously this would involve, within the lifetime of many who founded this new group and who were there, inventing the wholly spurious justification that the Leader - a pious Jew - was in the spiritual capital of his nation at a time when people went there on pilgrimage, on pilgrimage. How likely would that be? They probably had to tell old John and James the Leader's brother to shut up when they said, "You know, I'm sure it was round about August Bank Holiday...."
So a religion of death and resurrection and a freedom from spiritual oppression and the hope of new life, claims its key founding events happen in a city where its Leader might well have been, at a time when he might very well have been there, and writes down the story within the life time of those who could very well have been there - attaching the story of Easter to a spring festival indeed, a Jewish spring festival called Passover, which had a ritual meal that looks remarkably like the ritual meal with which the new group remembered its founder. How unlikely is that?
You're right. I should stop this wild speculation. Let's go with Bede's confident, enigmatic, one-sentence assertion that a Middle-eastern religion invented its main festival because it stole the idea from a tribe a thousand miles away. It's much more rational. We could add in that Joseph of Arimathea got the idea and brought it back, when he visited the Glastonbury garden centre to sell them his new thorn bush, bringing the non-existent boy Jesus with him. And buying a souvenir mug from the Grail shop. Yes, that's clearly right. How could I be so gullible?