I see this as likely to incite further discomfort

Gotta break a few eggs to make an omelette.

According to no authority, here is what I think is the standard protocol. If you know the offender, you pull their strings a bit - if they care how they appear to the people who they know, say it makes you want to avoid being seen with them, if they care about being high-class, say it's low-class, if they regularly care about strangers as people, use an ethical argument, if they care about being hard-working, say they're damaging the image of the company, etc.

If you don't know the offender you can't be so nuanced or even very friendly, but eggs, omelette, yadda yadda. If you or they are passing by with limited potential for escalation, feel free to insult their choice creatively. If it's a "sharing the elevator" kind of situation, you're going to have to put on your big boy britches (relative to the insults) and tell them politely that they're being incredibly uncool.