However, my response to this article was "Let's just get rid of the things." An unsafe library is a useless one.
Now, we don't know the actual breakdown of that 2/3s group, and there certainly are homeless people (including homeless children) who are not addicts and benefit immensely from the public library system. But it's not a great sales pitch to tell people that children's story time will be colocated in an area populated largely by "current and receiving addicts", and people who are 100% in favor of paying for meth addiction treatment centers may reasonably question why we'd store our large and expensive public book collection there.
Keep in mind, if libraries feel unsafe (perhaps because they are unsafe), wealthy people will find somewhere else for story time and books, it's the low income populations that will be denied this essential resource.
This is partly why, in my previous comment, I wanted to emphasize that many of the branch libraries around SF absolutely do feel safe, and are very welcoming and clean places for kids.