My neighbor's who are Witness spent 2 hours lighting sparklers and shooting fireworks, what does that mean?

Their daughter and my daughter ages 7 and 6 are good friends. There have been comments made to my daughter by theirs about how bad it is to celebrate birthdays and other holidays but I talk to my daughter about the differences people have and she deals with it perfectly. Last night on July 3rd my daughter joined them in lighting sparklers and shooting fireworks to after midnight. During this time, their daughter said, we don't celebrate holidays ever and Makenna (my daughter) knows that. What does this mean? To me they were celebrating even more than me who is not a Witness.