You can also see them in shelters or vehicles where kids have to do their homework by headlights. SO many have a fit when they read that they drink or smoke or eat fast food. One must think if they are simply bad habits or something to help them survive the helplessness of their situation. If you are sitting in a warm house with rent paid for you do not look at life quite the same way as one who is looking for a warm grate to sleep on. That booze may be the only way to get through the night. For some smoking takes the place of food. No it's not good for them but neither is dealing with rotten teeth complete with infection surging through their body. Neither is having to skip meds for they should be taking for medical conditions they may have. A fast food meal may be their last hot meal for awhile. It may remind them of better times or to feel like they are part of the human race if only while they savor that carb rich meal. It's also a time to actually eat where it is warm and when people are not always pointing at you as if you carry every disease known to mankind.
It is much easier to condemn then it is to try and help the many who may be in dire straights.
As for helping out no one says you have to drop a coin in their tin(if they have one). If you distrust people that much you can always drop a case of food at the local food pantry or write them a check.
Yes we have scammers and crooks every day--people taking when they should be giving. All we have to do is look to Washington to find a building full of them!