That's admittedly a shitty association.
Why I'm doing it:
The rest of January (well, January - April/June) will be incredibly stressful for me as soon as I'm healthy enough to leave the house.
Drinking alcohol tends to have a moderately negatively impact on my productivity, which I don't want.
I know from experience that citing dry January is easier in these situations than just saying no thank you.
There are just too many people that seem to have had a very hard time accepting that I'm not pregnant, dealing with health issues or an alcoholic (...) when I was in a similar situation in the past. (Dry January, sober October, being on a cleanse, lent etc. seem to be more readily accepted reasons.)
And it's not like drinking less is objectively bad or associated with negative health impacts etc. Dry January seems to be potentially beneficial for moderate to high drinkers without an alcohol use disorder (AFAIK).
It also reminds me that the next months will be tough and stressful but that it is temporary. And that I will have free weekends and evenings again this summer :-)