You don’t know their history if you see a beggar on the street.
You aren’t sure that if you help them with money, they’ll use this money in a very unethical way.
If someone asks for money on a social network, you don’t know, again, their history.
The solution in that case? Go to an NGO, tell them your story, make them spread your story, and vouch for you.
If such an NGO doesn’t exist (but I think it does), it needs to be invented.