* I'm a software engineer. I'm already highly-paid, so the marginal hedonic impact of a nice party is relatively small compared to its monetary cost.
* I'm nerdy, and prefer quiet, small, get-togethers centered around an activity, compared to large, loud, alcohol-fueled parties.
* Holiday parties are often in the evening, requiring me to schedule time for a work activity in typical non-work time. Community Service is often most reasonably performed in the day, making it an alternative activity during the workday.
* As a highly-paid engineer, I'm aware of differences in luck and circumstance that led to my current good fortune - giving back to the community has a relatively notable hedonic impact.
* As a software engineer, most of my work is non-tangible and abstract - I basically talk to a non-person, all day. Many types of community service involve physical labor, repairing or constructing a physical thing/place. This taps in to some core desire of humans, and thus also has notable hedonic impact.
* Community Service is good PR, for both the company and employee. Holiday parties risk negative PR, either for drunken scandals, visions of gilded-age excess, or both.
* The money that _could_ be spent on alcohol, catering, venue, DJs, and apparently modeling talent, I'd rather see spent on more direct benefits for employees - snacks, educational materials/career development, or just plain raises.
So, yeah, I would definitely consider the perks of working for a company that advertised that it did _not_ host large holiday parties, spent the budget elsewhere, and organized community service events.