No, I don't think it's hypocritical. Carol singing can be enjoyed as a get together and sing along. Traditional carols are a part of our culture and that has value even if you don't subscribe to the religious beliefs behind them. I want my kids to know traditional songs and stories, and what they mean to Christians I will teach them what we believe and where those beliefs differ.
However, there is definitely an argument to be made for secular carols, since some people consider encouraging children to sing religious songs to be indoctrinating them into that religion. Personally that's not something I feel strongly aout as long as it's not compulsory.