Is reading people's negative comments about doctors on the internet considered backbiting (gheebah), which is forbidden?

There is no harm in reading people's evaluations of the treating physician. This is not considered backbiting, even if it includes dispraise and warning, provided it is truthful, because there is a need for it. Backbiting is permissible for a legitimate, valid Shar'i purpose that cannot be achieved except through it, such as warning and advising Muslims, like discrediting narrators and witnesses who are unreliable.