I like everything about this except the name.
the word advent is religious.
the word advent is religious.
If you are religious, look upon this as a similar thing which reminds you of the season, building in anticipation of the final day.
If you are not religious, it's just a word with no special meaning other than the time of year. Same goes if you are not of a Christian religion.
Otherwise, it's just a normal word which means "the arrival of a notable person, thing, or event".
if it's not, why not use a nonreligious word?
What an utterly strange proclamation. On every level: the notion that speech should not be free, the notion that users cannot be trusted to figure out what the project is about if it's not "clearly marked" in this way, the notion that there is some harm that can be done by such a "religious project" or a "religious word," whatever that even means.