Your response is phrased in the form of a rebuttal, but I think I agree with everything you are saying, so far as I understand it, which leaves me to wonder if I didn't explain myself clearly.
I believe that the concept of "deserving" or "undeserving" poverty is not just unhelpful but actually misleading, and creates a great deal of unnecessary confusion. It is more useful to ignore the personal details and look at the systems. We can't change other people; we can rarely change ourselves; but we can certainly change systems, because they are human creations in the first place. So that's how we should approach poverty.
I am in favor of basic income as an improvement on and replacement for other forms of social support, for a variety of reasons: it seems like a more efficient way to move money around, it seems like a more effective way to distribute resources to people in need of them, and it seems overall like a more egalitarian, less judgemental way of dealing with a whole complex of problems which currently create a great deal of suffering. It is simple enough to feel like good engineering. It is fair enough to feel sustainable. It is non-ideological enough that I feel reasonably sure it would be difficult to use it as a mechanism of social control against weirdo outliers, like I am, but who aren't fortunate enough to have access to the same resources I do.
By "option to fuck up" I mean simply the freedom to do something other than mainstream opinion thinks you should. In these examples, people clearly believe it would be a bad idea for someone begging on the street to use the money they earn to buy alcohol. Well, on average, that's probably true. But just because someone is in a desperate way, I don't believe that gives me (or you, or anyone) the right to tell them what choices they should make. It's still their life. If I am willing to hand the guy on the street corner my spare $5, I have to be willing to accept that he's going to do whatever he thinks best with that money. If I can't be happy with that I shouldn't give him the money. But I believe that each person generally is the best judge of what is best for themself; I'd like it if the society around me would leave me free to make my own choices, not because I'm successful enough not to have to beg for money on the street, but because that's how I think we should all treat each other all the time, regardless of circumstances.