If it was the other way around, I still don't think everyone would be swapping to the 'normal' bumpers. The M or Sport bumpers look good naturally and had they been standard fitment on ALL E39's I doubt very much there'd be as much 'interest' in getting the standard ones.
People freak out because they like to follow what BMW officially put on their cars. In the UK, only the M5 E39 model had an M badge from factory on the trunk/bootlid, so on 'any' other E39, it gets frowned upon. In the USA, I believe the 2003 model year 540i M sport got the 'M' badge on the trunklid, and I 'think' it might be the same in a few other territories. Although some 'Sport' designated or 'optioned' cars got the little M badges on the door strips, wheels, steering wheel etc - some owners who don't quite know will then put M badges on the trunklid and/or front grille etc and thus, making the 'big deal' !