This is because chinese traders have a keen interest in NEM. Maybe it's not as secure as u have been told.
Where's the evidence for that? I haven't seen or heard of many peeps out of China, plenty elsewhere in Asia though. The Chinese seem to be more conservative when it comes to alts compared to other bits of the world.
The evidence is that its being pushed by btc38 and associated chinese news portals. Chinese are good at promotion. Im sure that they promote it in QQ groups to lure international sheeple into it, and will possibly start dropping nem once the advertising is done.