i tend to agree with this. in desperation i have had a handful of trippy DXM experiences, but they were more akin to a dirty, sick b-grade ketamine experience at best. there was one time where a bunch of friends got together and took mushrooms but i couldnt afford to pick up any and a couple other kids that were into the DXM thing were feeding it to me all night. this is the only time i had a "psychedelic" experience with this stuff. by psychedelic i mean ego-loss, not psychedelic in the classic acid/mushrooms/etc sense.
the ego-loss was VERY strong though and i had thought loops stronger than i ever had on genuine psychedelics. it was not pleasant. everything was incredibly strange and it almost hurt my brain to think. i pretty much just gave up and let the DXM take hold. from the limited knowledge i have of DXM, it was something like a "3rd plateau" experience. not unlike a K-hole, but with ketamine everything goes kind of blank/ethereal for me. with this, the little sensory perception i had was looped and repeated infinitely smearing through my warped sense of time. now if what i just said happened on LSD, it would have probably been awesome, but with this substance it was terribly unpleasant.
it sounds pretty crass but honestly i think DXM enthusiasts just need better drugs.