That's not my experience, but fair enough. What is the accepted term nowadays, then? Would you talk about the assistance-seekers in Kolkata? Is it different if you say 'people begging' as opposed to 'beggars'? A real danger with sanitising words that everybody understands is that it then serious downplays the circumstances of some of the most vulnerable people in society and makes their real problems sound like fluffy little puzzles.
Don’t make out like calling someone a beggar is a noble attempt to address the needs of the vulnerable. The word beggar reduces somebody to an act they are required to do to survive, and implies that it is their entire identity. It fails to recognise human dignity and individuality. It is associated with all kinds of negative connotations - laziness, entitlement, scrounging, piteousness, exclusion. That’s true whether the person you’re discussing lives in Kolkata or London.
You talk about the danger of ‘sanitising words’ as though it somehow helps vulnerable people to be referred to in degrading ways. How could that be true? Do you think a disabled person is better referred to as a cripple, or a moron? Do you recognise that doing so is offensive and wrong, or do you think they benefit from people resisting the urge to ‘sanitise’ their language?
A desperate impoverished single mum who sees no other option than selling her body so as to keep a roof over her kids' heads is not 'forced into prostitution', she's a 'sex worker', which makes her proud, empowered and gives her full agency over the person she aspires to be. Except it doesn't.
It is nobody’s business to tell any woman how to define herself and her experiences. If the woman in your scenario describes or views herself as having been forced into prostitution it’s very important to accept that and respect her views.
But if another woman considers herself a sex worker, it’s equally important to respect and uphold that too.
And if you are talking about sex workers broadly, as a class, it is worth considering that there is an evidenced link between using terms like ‘prostitute’ and people viewing women who do sex work in a negative way. It has been shown, for example, that when people read a news story about a woman who has been raped, they are less sympathetic and more likely to consider the attack to have been deserved or inevitable if the headline and or article use the word ‘prostitute’ to describe the woman in question. So insisting on use of a word which is so powerfully associated with dishonour and low morals actually makes people care less about the woman in question, not more.