The IE 800's frequency response is pretty v-shaped with emphasised bass and upper highs and eectric guitars do sound too "powerfull", that's a fact and even Sennheiser's official measurements prove that, albeit I can't approve calling the IE 800 "scam".
Yes, they are pretty colored sounding, but I guess that's intended.
Yes, they are somewhat artificial sounding, especially in the highs, but Sennheiser never announced them to sound accurate or natural. They sound gimmicky but that's not a bad thing when you are using them on the go.
Yes, they may be overpriced given their build quality (cables aren't user replacable and quite short).
But no, they are definitely not scam and I'll tell you my opinion why:
Even though they have a quite noticable treble emphasis there are no peaks in that area which is due to the Helmholtz resonator (one of the two holes on the back) which is tuned to ecpecially that area to eliminate peaks.
The bass emphasis does not bleed into the mids but stops in the fundamental tone area. In addition, the bass emphasis is pretty well made as it rises very evenly and holds the level even in the sub bass (the IE 8/80 have a mid bass emphasis with less level in the sub bass area unless you add more low end by adjusting the bass screw which will lead to slower bass with more bloat).
Mids are recessed but neither too dark nor too bright sounding.
Resolution is pretty good.
Distortion levels are very low.
Though the IE 800 has got dynamic transducers, the low end is firm, fast and solid.
Imo the IE 800s are surprisingly well sounding iems if you want that sound signature that is tuned to "fun".
That's just my opinion on the IE 800 and you may agree or disagree with it, I wouldn't mind, however, I am convinced that most of you will agree that one as an employee (or is Dr. Fang Bian even the CEO? I don't know, at least he works at HiFiMan.) does not simply publicly comment on another manufacturer's product like that in such an outrageously offensive manner.
I've only got the HE-400 from HiFiMan and it is also not sounding natural in the upper mids with that peak.
Just my 2 cents.