It is a very nationalistic holiday and, politics being what they are these days, the people around the op weren't celebrating Independence Day so much as gloating that the government in the body of the Supreme Court just succeeded in overturning precedent in restricting carrying guns in some places and in regard to Roe v Wade. She was horrified and disgusted about the latter in getting her rights undercut and taken away while everyone around her was celebrating it without a thought to consequences while she is highly aware of the risk to her life from it from this point forward. She lives in a very backward region of the country where they swear by the imaginary man in the clouds and think they and God believe the same things as long as it doesn't inconvenience them personally.

I am only answering you because I am assuming you aren't from the US and you are genuinely curious.