What position? If you let it pass, you encourage this kind of behaviour.

If they are working for a western company, they should adjust their behaviour, not the company. Just imagine working for an Indian company (or manager), and expecting them to tolerate your individualist behaviour and audacious questions. You would be punished immediately.

If it's a peer-to-peer relationship, all the more reason to be firm. If you don't speak up you will never be respected. And don't think that just because you keep quiet the shitty types of people won't stab you in your back at their first opportunity (ask me how I know).