I see two things here. The first is that I am surprised that there are a lot of states in the USA where gambling is not legalised. Gambling has its bad things, like alcohol for example, but it is more than proven that by prohibiting it you don't eliminate it, you leave it in the hands of mafias and you stop collecting taxes. And this brings me to the second part, that part of the taxes will be used to help the homeless seems to me to be a poor argument. What we have to do is to attack the root of the problem and try to avoid, or at least reduce the percentage of homeless people.
Then, as for the clothes that people may be wearing, I consider that a secondary issue.
Gambling makes people poor and in a country like the US, you are literally fucked you are out of money.
Smoking and drinking alcohol will ruin you financially too. See how expensive your health insurance will get when you consume both.
People in the US dont smoke or drink alcohol not because they hate these products. It is because they have done the math and they dont want to get robbed by the big pharma.
Gambling on the other hand has nothing to do with your physical health (your mental health is another story) and thats why there isnt any entity to keep you in line other than the government and the government always ban the stuff which cant have it under control.