Cotton picker, road to Bukhara
Fujifilm X-H2, Fujinon XF150-600mmF5.6-8 R LM OIS WR, f8 @ 1/170, ISO 125
Did you hear about the astronaut taking photos of Earth from outer space and complaining his shot was ruined because someone in New York moved?
When we photograph people from a distance, it's not that it's right or wrong, rather it creates a different story. Many of the famous travel photographers we follow use a close-up style, employing a wide-angle lens and getting very chummy with their subjects. Or they might have the confidence to walk up to anyone in the street and ask to take their photo – a tight head-and-shoulders. The stories that are inferred by these angles are quite different to a lone figure walking across a sand dune, but not all of us are confident about photographing people.
If this is you and you're simply not cut out to interact with people on a one-to-one basis or you're worried about what your subjects might think, say or do, then if you want to include people in your travel photos, you have no option but to shoot them from a distance. And it's more than okay!
Of course, if you have a fear of interacting with your subject, then don't choose a single person who is looking straight at you! You may be noticed and an interaction could follow!
Shooting people in a crowded market or street is a lot of fun. I like using a long telephoto lens (like a 300mm f2.8 or a 150-600mm) and sitting down somewhere quietly. I flip the LCD screen out and look down. Another photographer will know I'm shooting, but the average market visitor won't give you another thought.
The longer the lens, the easier it is to get a tight portrait without invading your subject's personal space. And one of the advantages of shooting long is that with a wide open aperture, it's quite easy to throw the background out of focus, highlighting your subject.
So, definitely nothing wrong with photographing people from a distance. And if you do get caught, you've got a head start for the getaway!