There is florist in the article that is introduced as someone who could pay rent from her savings. However, she has decided she would "rather conserve her money than pay bills now."
And even worse, there is a guy in there who still has a job, has the money, and isn't paying rent because of "solidarity" with the florist! What sort of weirdness is that? I feel sympathy for those in precarious finances who really can't pay, but then articles like this come with examples of people who can pay but don't because... theoretical "social injustice"? That surely doesn't make me sympathetic to any cause...
Solidarity is a principle of social justice [0]. It's very simple, and related to tragedies of the commons. When there is some common resource, solidarity is the idea that we should all adopt common attitudes towards that resource.
I can afford to pay my rent. I have no problems doing so. However, if I were to learn that my rental management group were facing a large rent rebellion, that I believed that the rebels had legitimate complaints, and that the rental management group could survive the rebellion by evicting all of the rebels but only if I paid my rent, then I would consider not paying my rent.
Therefore, I can imagine a situation where I would not pay my rent despite being able to afford it, and be expressing solidarity by doing so.
I don't really care whether or not you're sympathetic right now to this particular cause, but you should consider the principles behind the actions that people are taking, and spend some time putting yourself in everybody else's shoes.