It is inflammatory tactic to make those who already agree with you clap - but it won't convince those who disagree. It turns rational argument into attention seeking.

Its imprecise in that I expected to see a story about the deletionist problem. They are why I refuse to donate, I know I'm not alone.

Its interesting that expenses are out of control, but isn't what I expected.

It is slightly above clickbait titles "top ten reasons you'll never believe ..." but not much better.

It really isn't.

What makes cancer special isn't just that it grows. It's that it grows and thereby kills its host: it consumes the resources the host needs to live, or blocks tubes that need to stay open, or squashes things that are damaged by squashing, or whatever.

None of that seems applicable here. Wikipedia is getting more and more donation money, and spending it. That's only cancerous if it's spending the money on things that harm it, or if somehow this process is diverting resources away from things Wikipedia actually needs. There's no sign of any of that, so far as I can see, and to tell a scary story the article makes predictions of hypothetical future doom.

If those predictions come true then OK, we can say that Wikipedia has cancer (or maybe some other ailment that's a better analogy). For now, so far as I can see the analogy just isn't there unless you take "cancer" to mean absolutely anything that grows. I don't think that's a helpful way to use the term.

Okay, maybe it's just me.