Also, and this goes to basically everybody making the "but they stole it from the Pagans!” argument:
IT LITERALLY DOESN’T MATTER
I’m Jewish—Christians literally stole our entire fucking religion, wrote a sequel we never asked for, and then turned that sequel into a major blockbuster hit that resulted in thousands of years of Jewish persecution for sticking with the original.
The last supper was likely a Passover meal. That doesn’t mean it’s valid for me to burst into people’s homes on Easter and tell them they’re actually having a Jewish celebration because they stole it from us. Because Easter is a thingnow that exists completely separately from any Jewish traditions, and we can’t just take that back because it’s something else now.
Christianity has appropriated countless things from other religions, and that’s massively shitty. But denying that symbols, texts, and practices that have been integrated into and spread through Christianity aren’t Christian is both erroneous and counterproductive. You can’t pretend that cultural evolution doesn’t happen. It does. And it doesn’t matter whether or not trees were a Pagan thing, or when Christians started using them. Christmas trees are Christian now because Christians use them as decorative symbols for their Christian holiday, and Christians don’t get a free pass when they put them up in public spaces by claiming they’re secular or Pagan for that very reason.