Because that's how it is here (Russia). It's wide spread scheme - crime groups "cover" some territory (usually where there's a lot of walk traffic) and take money from all the beggars which stay on that territory.

Here you can see how beggar gives money to his criminal supervisor: https://www.youtube.com/watch?v=5TrRI1QyQ8g

There's a lot of info about it on youtube, but it's mostly in Russian. Beggars in good places can get 2-3 average salaries per month and most of those money goes to criminals. It's really ugly criminal business. As an example - there's such thing as "renting" small babies - because women with babies can gather more money. They drug babies so they would lie still in the hand of beggar women. So giving money to beggars is often same as giving funds to criminals here.