A pride flag is no more "sexual content" than a cross or a purity ring. That said, big displays of religious, political, and other types of identity are better left out of most workplaces. There are plenty of places to express that sort of thing without dragging your co-workers into it.
Discussion
Look, I only have like five tshirts and all of them has something along "fuck the state" theme 😂
At the risk of being hypocritical, This is perhaps the only identity I'd be OK with seeing overtly displayed.
Agreed. I don't expect someone to have a hyper-religious background as well.