It's easier to hope someone will have information on an individual who's is reported on. Someone might see the article and realise they saw her in a coffee shop with a man, looking very uneasy. And tip off police.
Whereas homelessness is a much harder thing to tackle. That requires government intervention rather than individual intervention from someone who saw something suspicious. And getting a government to care about homeless people is a huge ask.
I hate that we have a homelessness issue, and I hate that it's not reported on much at all. Things should be in the public eye, in hopes that people wrote to their local rep to try get help.
But it's more likely you'll find a missing person (dead or alive) by posting an article than it is likely you'll resolve homelessness.