The seventh element of religion is material expression. In other words, religions tend to have “stuff” which adherents use in their practice or to identify themselves with the faith. Rituals involve certain items and specific settings, even sometimes costumes or modes of dress.
Personally, I’ve noticed that the more deeply involved and committed I get to a cause, the more my collection of tshirts and sweatshirts grows. People knitted and crocheted thousands and thousands of pink pussy hats for the recent Women’s Marches, and are still knitting them. We paint signs and carry bullhorns, wear stickers and buttons and bracelets and flags.
Much like many traditional religions, most would say no one needs the “stuff” to participate, but the stuff is nevertheless ubiquitous and common.
We like the stuff. It reinforces our allegiance and message visually as a way to attract those who are with us and confront those who are not. It amplifies our voices. It lets us say what we wish to say even when we can’t get our voices heard.