I was once buying a suit in a store that sells hats as well and a young boy asked which hats were in style. Whether one wears a uniform or not people who want to will find a way to express themeselves with dress.
It’s simply a uniform that has become known as “Jewish.”
Most Rabanim where white shirts because it is plain and respectful. Rabanim are supposed to invest in their appearance as those who represent the Torah. A representative of Torah must dress respectfully at all times. White shirts are the best way to go. I think all grooms where white, it’s simple and elegant, anything else distracts from the wearer.
No one will tell you Jews must wear white, although al pi kabala there is an inyan to do so.
Black suits are just neutral. There are Halachot about wearing black on Shabbat.