Lemme have another go at this.
If there are different laws for different groups, then the differences between the groups will grow. People will join Camp A or Camp 5 or Camp Potato, and their actions will depend upon what camp they are, and are not, in. Even those—especially those—who don’t care one whit about camps will be pressured to choose, to pick a side.
Absent a neutral law, neutrality is hard to maintain.
And absent neutrality, pluralism is hard to maintain.