Generally the conservative argument is that welfare money should be earned in some way, essentially by doing socially constructive things (ie staying off drugs, applying for jobs, not committing crime). The goal is to direct resources to people who can be helped and are actually putting in effort to take care of themselves, on the assumption that those people can take some assistance and really benefit from it, whereas the addict who is sleeping on the street will just use tax money to buy more drugs.
A common liberal argument (not the only one but a common one), is that it’s more important to help “those in need,” no strings attached, that you can’t expect them to get out of the gutter until their basic needs are met and even if giving them money just enables their habit you have to “do something” and giving them clean needles and cash is better than “doing nothing.”
One of the problems that manifests all over the world in varying degrees is the tension between doing “something” which can easily harm more than it helps (the conservatives tend to point to this), and doing ENOUGH to actually help someone (or robust social services to rehabilitate people). In the US it used to be common for people to be institutionalized, they’d have all their needs met and in most cases get some semblance of help, albeit at a cost to their freedom. Well, nobody really liked that system since it was very expensive and was prone to human rights problems (if someone is too mentally ill to consent and you try and experimental treatment on them, are you helping or using them as a lab rat?). So now those people are on the street.
At the end of the day it’s a very difficult set of economic and moral problems to solve, and demonizing the political party you dislike and labeling them as heartless villains accomplishes exactly nothing.
What arguably would help is sane housing and public health policies so people could afford a roof over their heads and get medical treatment when needed without having to have an upper class job to pay for it.