It's because as I said before, color temp which was once a useful measure has been raped in the sake of marketing.
5 years ago the choices for MH bulbs were pretty slim. You had a 5500K bulb, a 6500K from Coralife in 175W, the Iwasaki 65's, the 10K Coraldeath, the 10K Germans and the 14K Belgian/20K Radiums
The 10,000K Germans became very popular, because of the clean white light. Some people would then add ALOT of actinic to get a deeper blue look as well. When you looked at what was popular what was being said in online forums and what was selling etc the manufacturers kept hearing the mantra "10K, 10K, 10K, 10K, 10K, 10K" it was like a Gregorian Chant to them.
Since then with the exception of the 12K ALS bulb anything that has come out since has had the label 10K slapped on it regardless of what the actual CCT was. In fact if Venture Lighting tomorrow slapped a 10K label on their 5500K bulb most people wouldn't care and I'm betting their sales would go up.
Thus when you are buying a bulb talk to someone who has actually seen it. If it doesn't say "German" and it's a 10-12K bulb you can expect it to be very blue. The problem with the blue bulbs is that while they look okay to many their actual performance compared to the Germans or the lower K bulbs is pretty horrid when it comes to PAR and lumen output.
The great 12K ALS migration of 2000 was comical to watch. December/January the bulb hit the market and people snapped them up like crazy. Within 90 days most people were back with what they had before either from the failure rate of the bulb or because of the huge drop in PAR that resulted when they went from a 250 Iwasaki to the 12K bulb and their corals started to be unhappy.