Of course it's a side effect of rent control, but it's not a necessary side-effect of rent control. Rent control laws do allow for increases to cover maintenance, so the money is there. It's not like doing away with rent-control would have a better outcome from the POV of the tenant - instead of living in a gradually deteriorating building, they'd just have been kicked out.

BTW, I'm not a necessarily a fan of rent control, I just like its goal. I really don't know enough about the issue to make an informed policy decision either way. My main point originally was just that this article was terrible - stupidly reasoned and completely lacking in meaningful evidence that would let me make an informed policy decision.