In a sense, July 4th is the most religious of all the holidays.
Have I lost my marbles???
No.
I don't have marbles. I stopped playing with marbles back when Jimmy Carter was President [whose wife Roslyn, incidentally, recently lost HER marbles. Jimmy calls her "Shoshie"].
So let me get my MAGA hat on and explain.
All the holidays have mitzvos connected to them. July 4th has no mitzvos. It isn't even a "Jewish" holiday per se. Although it IS Jewish in the sense that Jews really enjoy it. The foundations, the roots, the bases for mitzvos, before you can get to mitzvos, are MIDDOS TOVOS [מהרח"ו]!!! No middos tovos - nothing.
One of the real foundational middos tovos upon which our whole lives should be based is הכרת הטוב - gratitude! Gratitude to Hashem EVERY SECOND for all of His endless brachos [99.99999 percent of which we tend to take for granted and only remember how blessed we were when we lose them]. And gratitude to people for all they have done for us. A person w/o the middah of הכרת הטוב is upgefregt in gantzen ["rotten scoundrel" in Latin].
One of my favorite Ramban's [and that is saying a lot b/c there are soooo many AWE-SOME Rambans] is his explanation on the pasuk עם נבל ולא חכם. A person who repays good with bad is likened to a נבילה ["carcass" in old French].
America has been SOOOOOOOOOOOOOOOOOOOOOOOO incredibly good to us. Not only to us Jews but to hundreds of millions others as well. After all the complaints - there are probably hundreds of millions of people if not billions who would LOVE to live in the good ol' USA. I personally have such strong positive feelings about it, I would live there myself if not for the fact that I received a Divine command telling me to live in Israel and that the level of spirituality leaves more than one can describe to be desired [and that I couldn't afford Yeshiva tuition for the life of me]. But otherwise, as far as the freedom and opportunity afforded there - it has no equal [except for EY which is EY so it has no equal.]
We suffered so much in other countries and our experience as a people in the US has been MUCH MUCH more positive [albeit not perfect]. Of course, many Jews lost their Yiddishkeit in America but that was all voluntary as opposed to in Europe where we were often tortured and oppressed for being Torah Jews. [I should note that an exception to this was the horrific period where in order to earn a living one had to work on Shabbos. Nobody was forcing anyone to work but the alternative was starvation].
The Jews have achieved such success in America not only materially but spiritually as well. [They even named two States in our honor - Jew York and Jew Jersey.] Not only that but many many people are able to live comfortably in ארץ ישראל b/c of their families earlier success in the US. And the US has given Israel billions over the years.
So it behooves us to display the middah of הכרת הטוב not only on July 4th but every day.