Your not "pointing it out." You are just saying it.
Let's go through this then.
First of all, there are 3 issues that tend to be conflated:
1. When and why was 25 Dec identified as the (supposed) date for Jesus' birth? (or if you prefer why is it in winter) -
My view: Probably 2nd/3rd C. due to a variety of related exegetical traditions from Daniel, Luke, etc and other theological assumptions combined with a desire to calculate calendars of important dates.
2. When and why did this become a liturgical feast day -
probably 4th C in Rome - hard to say exactly why, but timing around Nicaea may suggest connection to mono/dyaphysite internal disputes
3. What are the origins of the Christmas rituals, decoration and festivities (trees, presents, etc.) - My view: it's certainly possible there was some cultural continuity, but most of our modern traditions seem to be just that: modern. There is no evidence AFAIK, of any pagan tradition that was also a medieval tradition and is also a modern tradition. There is very little evidence of many of the supposed pagan traditions even being pagan traditions (Saturnalia was not associated with evergreens, etc).
You literally cannot admit that Tacitus described yule in Germania in 98 CE.
You are asserting this, not providing evidence.
AFAIK, Tacitus did not describe Yule. If you have evidence please quote it here.
AFAIK, Tacitus described a generic Germanic festival of some kind. In this case so what?
All relevant societies had festivals in all seasons. This is so obvious it doesn't need to be said.
Other than "post hoc ergo propter hoc", what is the
evidence of any causative connection between any generic feast days and Christmas, Easter, etc?
Or that Pope Gregory I advised the Bishop at Mellitus that pagan temples be converted into churches and that pagan festivals, such as Yule-like celebrations, be "baptized" with Christian significance to ease the transition for converts.
People seem to take a grab bag of 3000 years of pagan/Christian history across vast distances of time and geography and then just pick and choose whatever matches their presumptions without any actual attempt to contextualise the information.
7th C Britain (or any part of Northern Europe at any time) has
absolutely nothing to do with:
1. When and why was 25 Dec identified as the (supposed) date for Jesus' birth? (or if you prefer why is it in winter)
2. When and why did this become a liturgical feast day
If you think it has something to do with:
3. What are the origins of the Christmas rituals, decoration and festivities (trees, presents, etc.)
Feel free to present some evidence.
If you don't think it has anything to do with any of these, then I'm not sure what your point is, can you please explain what you consider to be the the pertinent point.
Also, the letter doesn't really support your point anyway:
Very often quoted, but rarely in full, is a letter sent by Pope Gregory to Abbot Mellitus, who was about to join Augustine in England, in the year 601... Gregory then turns to festivals:
And because they have been used to slaughter many oxen in the sacrifices to devils, some solemnity must be exchanged for them on this account, as that on the day of the dedication, or the nativities of the holy martyrs whose relics are there deposited, they may build themselves huts of the boughs of trees, about those churches that have been turned to that use from temples, and celebrate the solemnity with religious feasting, and no more offer beasts to the Devil, but kill cattle to the praise of God in their eating, and return thanks to the Giver of all things . . .
To schedule the new feasts to coincide with the anniversary of the church’s dedication, or the feast-day of its patron saint, would almost inevitably break any previous links with the agricultural cycle or seasonal turning-points— the letter does not advise picking saints whose days match pagan festivals.
It is in any case doubtful that the policy outlined in this letter was widely adopted. In the same year, Pope Gregory wrote to King Ethelbert, urging him to ‘abolish the worship of idols and destroy their shrines’ (Bede; book 1, chapter 32). The few other relevant documents include no other reference to any policy of accommodation, but on the contrary mention several temples deliberately destroyed; archaeology has so far found no traces of pagan Saxon shrines under any churches.
Source: Oxford Dictionary of English Folklore
Or that Griped about the persistence of pagan festivals even after Christian appropriation had begun.
Pointing out that Saturnalia and Christmas were celebrated alongside each other in for over a century and that no one noted that they considered it a replacement or an attempted marketing ploy is not a "gripe", it is an evidence based argument against the idea that it was a replacement or marketing ploy.
Did you bother to check on any of that? Or did you just ignore it and continue to say Nuh-uh, no cultural subsumption here?!
Yes. The sources don't say what you claim IMO, and even if they did they still don't really support your vague assertions.
If people just google this topic they will find all kinds of erroneous claims. That is why you need to be specific.
Cultural "borrowing" is certainly possible, but we would need to see evidence of some kind. Something specific, not just post hoc ergo propter hoc or a random 7th C quote that doesn't quite link to anything specific.
Feel free to make an explicit connection based on evidence if you like and we can consider it.
Because I certainly looked into your claims about Sol Invictus.
Excellent. Feel free to offer your thought and discussions on the multiple peer-reviewed scholarly articles and their contents.
www.goarch.org