Well, you’re very good at copying and pasting from Wikipedia. 
But that only establishes that there is a lot of debate on the subject. This in itself contradicts your assertion that it’s a settled matter, and undermines your initial post. It’s also wise to be cautious about Wikipedia on subjects like this, because such articles tend to be fiercely edited by Christians.
On John Chrysostom, did you ever bother to read the quote I gave a year ago?
Ddid I ever say there wasnt debate?
“AD tract erroneously attributed to John Chrysostom (De Solstitiis et Aequinoctiis)”
https://penelope.uchicago.edu/~grout/encyclopaedia_romana/calendar/invictus.html
Regardless of whether Christmas’ date was “borrowed” from the Saturnalia* or Sol Invictus, it is almost certainly true that the dates of all of them were chosen, at least indirectly, to match the winter (in northern hemisphere) solstice. Many other cultures also celebrated that date including the Norse, the Celts, the Chinese, the Japanese, and various cultures in the new world. Julian calendar recognized December 25th as the solstice. (It was only later set to December 21st because the Julian calendar fell behind the sun by about 3 days every 400 years. It was set indirectly because the Spring Equinox was known to be about March 21st (and then defined to be March 21) when the rule for determining the date of Easter was set in 325 CE by the Council of Nicaea.
*Saturnalia may itself had been celebrated on December 17 as the OP claims, but it was also the beginning of a week-long celebration.
The following quotes from your OP suggests you are far from openminded to debate:
There is a bit of evidence to back up the Sol/Christmas timing issue. But there is really no “bit” of evidence to refute it. So it’s an unsettled matter and remain so. But with the pro-Sol/Christmas side having an edge. The Saturnalia thing is more iffy which makes it weird you focus so much on that. A lot of straw man type stuff being thrown out.
If you read some of your own reference, you will see that, while it’s not accepted now that the tract was by John Chrysostom (on the basis of the use of ‘African turns of phrase’ and Syriac terms), it’s not disputed that it’s a Christian text from the early 4th century:
The whole book by Susan K. Roll seems very interesting.
Most of her long section on The Invincible Sun and the Feast of Christ’s Birth is not available for preview, unfortunately, but she says at the beginning of that section:
I understand the “Fighting ignorance” part, but fail to understand the debate and need to bring the subject to the table. As a believer, I don’t place any significance or important on Jesus’ birth date. While there is cause for celebration of his birth, whatever day it may be, it greatly pales in comparison to his (alleged/mythical for non-believers) death and rise from the dead. I’ve stated to a number of clergy and those with stronger faith than me that “Everybody is born, but only one person rose from the dead as he said he would.” I don’t know if they agree with my statement or are just gobsmacked by my statement, but the conversation usually ends there.
To hopefully clarify and expand on my statement above, the way I see it, “Fighting ignorance” is only valid if solid empirical evidence refuting the ignorance can be provided. As posted above, there is no solid empirical evidence for Dec 25th being or not being the basis for the date of Christmas, so it’s not Fighting Ignorance by stating a fact, but an opinion.
For those who view Dec 25th as the birth date of Jesus, it’s a matter of belief and celebration of an event, IMHO, no different than anyone with an unknown birth date. For those don’t believe Jesus was the promised Messiah or don’t believe he even existed, Christmas may just be day to show caring and good will to others. In either case, whether or not it’s based on Saturnalia or any other historic day doesn’t validate or invalidate it’s significance for those who choose to celebrate.
I notice that people who complain about wiki cites dont have much in the way of cites themselves.
Oh yes, certainly, but yes indirectly. They used the Spring equinox for the annunciation, thus the Winter solstice is the birth day- more or less. They mostly seemed to pick March for the annunciation based upon mystical reasons, altho there is some tradition to back that.
In no way am I implying that Dec 25th is the right date. Sure, based upon some old traditions, etc it’s got better than a 1/365 chance but it far more likely to be wrong than right.
There is some debate on both sides whether Christmas might have been influenced by Mithraism, but no scholar argues for Saturnalia.
Well, yes, since the date of the Annunciation is based upon the solar calendar, with the Equinox, Solstice etc. It is connected.
Just recently this was posted in GD:
SuntanLotion "it never started as having to do with God. It was a saturnalia, sun didn’t die holiday and the church co-opted it. "
https://boards.straightdope.com/sdmb/showthread.php?t=886858
post 27.