Many people on the street have been in care, and the longer you've been cared for by social services, the more likely it is that you develop what's known as 'learned helplessness', ie expecting others to look after you, or give you money, and not having the confidence or the experience to make...
Some hostels you don't even have to be clean or sober, otherwise there'd be a lot more people sleeping in doorways. You only get asked to leave if you are dealing drugs or are aggressive towards other hostel residents, many of whom are very vulnerable.
If you live in Brighton, you could tell yourself that you are already funding their hostel/day care/addiction/keyworker/rehab etc through your council tax. If you want to give a little more to help fund their addiction too, that's up to you.
But only people with a Brighton connection are...