|By Pixuk (Own work) [CC BY-SA 4.0]|
Some examples are considered more artistic than others (e.g., Piss Christ), but most seem to share the common goal of provoking outrage. When Iranians burn an effigy of a U.S. president in front of the TV cameras, they expect outrage. If they didn't, they would be unlikely to bother. When Fred Phelps and his merry band of Christian extremists picketed a funeral, they expected the same. They would show up and do their thing in order to rattle some cages.
There is a much gentler version of this phenomenon that seems less about serious protest and the provocation of outrage and more about mockery for its own sake, in-group signaling, or even entertainment. For example, many atheists create images or videos mocking all sorts of religious symbols, figures, traditions, and holidays. While some may be engaging in forms of protest when they do this, I suspect that many more have other motives (e.g., seeking to entertain other atheists). Outraging the religious, if it happens at all, is just a bonus.
In the run up to Christmas this year, I have seen plenty of the usual mockery of the holiday from atheists, most of it in the form of the same memes that circulate every December. I have also seen many atheists speaking out against it, more than I remember in previous years. Their arguments generally take the position that it is unnecessarily inflammatory and cruel, hypocritical (because many of the atheists mocking Christmas are preparing to celebrate it themselves), juvenile, or counterproductive in various ways.
I suspect one's answer to the "should atheists be mocking Christmas" question depends on many factors (e.g., whether one is celebrating Christmas oneself, whether one is anti-theistic, the degree of respect one has for various religious traditions). It also strikes me as a question without one correct answer. I can easily imagine reasonable people disagreeing with one another and providing cogent reasons for their opinions. I'm not seeing much of this taking place, but I can imagine it happening among rational persons.
I suppose my opinion on this question would be that there is nothing necessarily wrong with taking a poke or two at various holidays, especially if it really is a form of protest against Christian privilege. It does not bother me to see others doing this, and I might do so myself. Maybe some good could come from reminding Christians that they do not own December and that theirs is not the only holiday observed this month. At the same time, mocking Christmas can easily be overdone. When one gets carried away with this, one can end up not looking particularly reasonable. And I suppose that going too far could lend credence to the common stereotype of atheist as Grinch without much benefit to show for it.
In the end, I find that there are plenty of more important things on which I'd prefer to spend my time. Besides, I'm perfectly content to let Christians have Christmas. It isn't like I want any part of it, and I kind of like to see them try to be a little bit nicer to each other for one day a year.