Isn’t that the “core” principle of being liberal? Free to believe whatever you’re believing in without forcing or shaming others from not following your ideology?. I find it fair to ban the flags as long as other religions can’t announce theirs too like curches bell or mosques Azan or whatever. Why would you teach my kids about X ideology in school while others aren’t allowed to do the same? The meaning of multiculturalism and diversity is not shoving someone ideology into others’, and certainly not getting upset when people don’t like your ideology.