The rule in my school district is that if you celebrate one holiday, you must celebrate all holidays. So in December, we do a little Hanukkah, Christmas, and Kwanza, although I have yet to have a student that actually celebrates Kwanza. I've never had an issue with any of the 'holiday' gifts I've given students, most of which have been snowflake-themed. Interestingly, this year I noticed that I got quite a few Christmas gifts and greetings from my Muslim students.
IMO, this is the other parent's fault. I have had quite a few parents inform me that they do not want their child celebrating Halloween. Luckily, they have always notified me in advance, so I am able to make sure that their children are not exposed to anything they find offensive. If a parent complained after the fact, I would politely let them know that they should have let me know ahead of time.