Adventus evidently feels the same way as I do about them, and writes:
If you wade through that (as you should, if you want to know something verifiable about history), you reach this conclusion:Some years ago I had the job of marking some student assignments on this very topic. The assignment was part of a missiology course at the University of South Africa. It had not been set by me, so I had to read everything on the reading list to make sure I knew where the students would be coming from. Most of the reading was articles in various respectable (peer-reviewed) theological journals. I was rather surprised to see how many unsubstantiated assertions there were in these articles, and decided to do a bit of research on my own and tried to find out when Christians began to observe the Feast of the Nativity of Christ from contemporary sources, and why they did so. And what struck me was the remarkable absence of contemporary sources.The present writer in inclined to think that, be the origin of the feast in East or West, and though the abundance of analogous midwinter festivals may indefinitely have helped the choice of the December date, the same instinct which set Natalis Invicti at the winter solstice will have sufficed, apart from deliberate adaptation or curious calculation, to set the Christian feast there too.
Some of the assertions were based on wild assumptions and speculations made by 19th century scholars. Or, more often, some historian had made a tentative hypothesis, and those who cited him did so as if it had become and absolute certainty.
Eventually, in marking the assignment, I found that most of it was urging the students to use their sources critically. It appeared that many missiologists are given to speculation, and are not familiar with church history, or even secular history. And church historians are very often not aware of the missiological implications of the matter they deal with. In the matter of Christmas, many of the assertions are based on huge anachronisms, which even an elementary knowledge of history would enable people to see through.
Anyway, Adventus also seems to have got sick of these muddled speculations and has taken some pains to set the record straight, or at least straighter. It's worth reading.