Why is "...and others" wrong in this sentence?

Grammatically it's okay because you could say, e.g.

I spoke to John, Mary and others.

As far as I am aware 'others' when used as a pronoun, conventionally only ever refers to people. I don't think it would apply to family pets - maybe not even young children. Thus I would say it is an idiomatic usage.

Note: Please refer to remarks in the comments below this question for further insights.

In this specific example “others” is not grammatically correct. It needs “holidays” in there somewhere.

“... other holidays.” would be fine. So would “... most holidays: Thanksgiving, Christmas, and others.”

Notable exceptions to this rule would be headlines and signs, which routinely break normal grammatical rules in the interest of brevity.