I think that it's sad that some people get upset when they don't get cards, and also that it's sad that others feel guilt tripped into buying, writing and posting them.
The 'tradition' is something that most of us grew up with, but it's not something that's been happening for hundreds of years. It started in Victorian times when cards were hand made love tokens, which is probably where the idea that they represent 'making an effort' and that they show how much people are loved comes from. They would only have been sent by those with the money and time to make them and send them. It is much more recently that they became mass produced, but those connotations have stuck.
They have picked up other connotations on the way. When I was a child, my mum would buy huge boxes of cards, and sort them into 'best' ones for good friends, 'average' ones for neighbours and colleagues, and 'the rest' for last-minute ones that needed to be sent if a card arrived unexpectedly. Most people seemed to do the same. It was pretty easy to tell where you sat on someone's priority list by which card you got
. I don't see that as being about love, but about social hierarchies.
Men very rarely wrote any, which meant that it was another thing for women to do at an already busy time of year. It was also a way of keeping women in line, as the social ramifications of missing someone out were real, and writing them out and organising lists took time. Mum used to write out cards for my father's colleagues and the people he managed, even though she knew hardly any of them. They would have been upset if 'he' didn't send them one, as it was taken as a sign of a caring boss. He was a civil servant, not a paternalistic Squire! Again, social hierarchies, not love.
As I grew up I could see that they were also about shows of apparent popularity. Schools had postboxes for children to post their cards, and they were handed out before playtime in public. Everyone could see how many cards everyone else got, and could compare that to their own haul. Parents were pressured into buying dozens of the things, particularly if they had more than one child, and houses overflowed with them on every horizontal surface and on every wall.
When I got married I was given a book in which to record cards sent and received. My mum had one the same, and would check cards in and out like she was reconciling a bank account. There was huge relief if there was a zero balance on the last post day, a sigh if she got one that had not been reciprocated (children were sent to deliver an 'emergency' one if the address was nearby), and those who 'hadn't bothered' got a tick against them - two consecutive ticks meant they were crossed out and were only restored to 'The List' if they came back into the fold and sent one. The phrase 'She's off my Christmas card list' was widely used (semi jokingly) about people who had been demoted in the friendship stakes, but with whom there hadn't been an actual fall-out.
When I was working and my children were at school, the whole card thing became an annual nightmare. The house was filled with the things, my colleagues, Mr Dog's colleagues, two lots of cards from each child's whole class (by this time, anti-bullying policies had come on stream, and leaving anyone out was not encouraged), plus those from extended family we never saw from one year to the next, and actual friends. Each one had to be reciprocated, although I divided this strictly between us all. Mr Dog did his colleagues and family, I mine, and the children their own. I still had to nudge them all, though, and pretty much always bought the cards. Where was the love?
Is it any wonder that people are sick of it all? Getting something that was only sent because the sender knew that they would be 'struck off' if they hadn't bothered, or because the sender's wife or mother had badgered them to send it is no sign of love or popularity, any more than not sending them is a sign of lack of care.
The very fact that people question those who make excuses says it all, really. 'Does her charity donation equate to the cost of cards?' puts the whole charade onto a financial transaction footing, only sending them to those who send back makes a mockery of genuine friendship, and weighing up someone's perceived carbon footprint against the carbon cost of cards is massively intrusive.
I send a couple to those who will not change their views - all much older than I am. It doesn't necessarily mean that I love those people more than those who don't get one - just that I don't want to deliberately hurt anyone. Otherwise, I stopped buying into the whole thing years ago.