Of course the whole thread here is skewed by the fact that he was disciplined for disobedience, not for the display of a palm cross
Whilst not up to complete speed with all the details, Boudi, I think that he was disciplined because he happened to contravene a particular rule with a particular item - after all, most people will decorate their van cabs with something (even if unpaid parking tickets, I've seen in one case!!). This particular item causes offence but, interestingly enough, not particularly amongst those who are usually cast as the offended - Muslims, Hindus, etc.