Disrespectful to whom? A chemical? Yourself? A drug experience?
It's a preference thing, not necessarily dangerous. It's your opinion, that it's disrespectful, IMO, it can be a good time. I don't take acid to have religious experiences, raise my vibrations, or anything else like that.
I think pot has a better chance of increasing bad trips more than booze. LSD and a few drinks is a fine combo for a party.
While it wasn't really me that said disrespectful, I feel that I have to respond.
I used to agree with your point, also what is relevant here IMO, I never used to see the point in rituals of any kind.
But after having been put in my place using DMT, and also having had transcendental experiences when I prepared pretty much in a ritual way before blasting off with DMT (but also other white knuckle experiences)... I realized something:
Psychedelic effect is mind-manifestation. It is an experience that comes from within yourself and the atmosphere of it is a result of what you bring to the table. It is mindset, setting, and that includes a feeling of respect towards this phenomenon even though there is no other person involved. That's super weird but it makes a lot of sense. If you (or I at least) just haphazardly ingest say DMT or 5-MeO-DMT then I just get a jumble of the unrest and unprocessed contents of my mind, shredded and shattered, back to me. But if I ritualistically take a moment to clear my mind in preparation I get beautiful things from my subconscious without the clutter of an unrestful consciousness.
It helps SO much if you are used to meditating, even occasionally, because it's the same deal basically only not so acutely vital on a short term.
None of this even has anything to do with beliefs, if you ask me, it is simply an effective method of tripping more safely, mentally stably and responsibly.
Whether having a drink before tripping is enough to call it bad preparation and thus bad practice, is up for debate here and like I suggested I think it depends on how much you drink and even more what kind of emotional intentions are involved with the drinking. Those can be harmless but also very harmful. And that is exactly what may be very irresponsible to start out on when going into a trip - more so than hangovers or anything like that.