I've seen several religious looking Christmas cards just going past shops.
I'm with those who said it's likely a misunderstanding or the employee just didn't want to get into it what that customer meant by a religious card. That might be sad, but I can understand wanting to move things along quickly particularly if it was a small shop where what's on display is pretty self evident and leaving the counter may cause other customers to leave.
What matters is we celebrate it at the darkest time of the year - and that's why they put the celebration around the time of other deep winter festivals
While there are some theories that fusing Christian ideas with celebrations already going on in winter (though which celebration varies by theory), the earliest references to that date are largely more focused on when Jesus was conceived and then doing over-rudimentary maths that I think don't really understand how pregnancy works. There was some ideas that he must have been conceived either on the same date he died (this is said of a few Biblical and similar figures) or around the Spring Equinox and then just counted from there. I don't really think the early church that fixed the date had much purpose of ensuring it was in the darkest time of year, at least I've not seen much evidence for that, anymore than I think the move of All Saints Day from May to October really had much care for what season it was in.
Never heard or seen written one such objection.
Wrestling with the Bible has a long tradition, both in content and - even more in recent years - how the history of how they were created, copied, translation shifts, and such that made them into their current forms and how that is used by modern churches. The Christian deconstruction movements which have been growing for the last couple of decades both from devout Christians - possibly in response to the vocal issues with those who go on about it being literal and inerrant - and those who were raised in and either question aspects of or have left the religion.
The discussion around whether a child can really give consent to a deity is a common talking point, particularly in how that idea is used in some modern churches with how children of that age are viewed (that and whether Paul was one of the false prophets Jesus warned about as he practically ticks every box, that might actually be the most common talking point in recent years with more recognition of the denominations that exclude works attributed to him and some being of the opinion that certain churches follow Paul more than Jesus).
The archangel Gabriel explained God’s plan for her to conceive, and Mary gave her consent in the following words
Quoting the gospels as evidence of consent makes sense if you think they're literal and inerrant & that a deity can never be wrong.
If you consider they were anonymous for centuries before the church put 'as written by' on them, are currently thought to have been written at least decades if not longer after the events, that they were written in a language the apostles were unlikely to speak and that they were largely illiterate and the Luke excludes himself as an apostle (he knew Paul, not Jesus), that literacy in that time was often just knowing how to read and write one's name and be able to copy and that any manuscript study of the texts is a copy of a copy...of one of those copies, that even in those copies we can see changes that were made - thing written over - quoting scripture is the start of a discussion into the concept, not the end.
And there is nothing in early church history I've seen that suggests that the dating had anything to do with Christ being a light to the world. That's a nice modern interpretation which I think is lovely, but there is little evidence that the early church thought that when it fixed the date.
many Old Testament stories attributing deaths to acts of God were simply allegorical, or down to the primitive tribesmen of the time seeking explanations for natural or human events.
Many New Testament stories can be viewed as allegory as well - including Mary's consent.
It does not in the least follow that God shared their views or took any part in mass murder.
There are several mass murders attributed to his direct action along with those that were his direct command. Treating all of the bad things as allegory of natural phenomenons and 'primitive' people (like Jesus?) and all the nice things as real is part of why the deconstruction movement has been growing. Many can see how harmful it has been to the church to continuously erase and push aside the problems in the text - in content, creation, and on-going changes and uses - when it's still used as the standard and an icon of faith.