I think it's because most religions, by their exclusive natures, are divisive and offensive to many. Many current and historical wars have been fought over religion, so some of their outward symbols carry a political message, whether intended or not.
Wearing outward symbols with a political message is banned among civil servants. If you wonder why, ask yourself how you would feel showing up to the welfare office and asking for service from an employee with a gold Trump necklace or a MAGA hat. Or, more prosaically, imagine getting pulled over by a cop for speeding. You are a Muslim wearing a keffiyeh and the officer is a Jew wearing a yarmulka (skull cap). You know that police have discretion to give you a ticket or a warning. He eyes your keffiyeh skeptically, you respond with a look of defiance, and he gives you a ticket. You might suspect that you got a ticket instead of a warning because the cop is a Jew and he saw your apparent support for the Palestinians. Now, of course, all of this could happen without the overt symbology, but the government would rather not open itself up to such obvious accusations.
These laws ban overt religious symbols only. If you want to wear magic Mormon underwear or a small cross or star of David or crescent moon under your shirt, you can. You can even wear Trump-themed butt plug if you want to.
But fuck all of these cults and their symbols.
I will never understand why these corporations spend big bucks on this cringe. I've been to one such event and I was shocked. What's worse is that long-serving people said you had to act as if you were enjoying it or else you'd hear from your manager afterwards. Imagine a bunch of middle-aged men at a sales conference shaking their hips and pretending to enjoy a cheesy rap battle. What an utterly soul crushing, suicidal-thought-inducing experience. I can't tell if senior management actually believes that this sort of corporate cringe is inspiring, or if they do it purposely to crush your soul and make you into a servile automaton. Are they out of touch or is it an Orwellian power move?