By this logic we should not give anything to anyone without an intensive background check,
That is the Halacha, which is why many larger areas have a Va’ad Tzedaka that does the checking for you. It is also why you are better off providing items (such as food or clothes) to Aniyim, or directly paying their grocery or medical bill, and not money, where appropriate. Part of the sickness is that people buy what they don’t need (as an extreme, drugs), and that doesn’t help them at all.
shulchanhashalem – Well said.
Once again, I’ll point out that there are Halachos of Tzedaka just like there are Halachos of Shechitah or Basar V’Chalav. Ask your LOR if you have questions on whom to give and how much.