What makes you say he shouldn’t have said it? Would McCain EVER hold his tongue against Trump or another republican?
The US senate is a debating society. The CIA is an intelligence service and a damn good one. https://www.telegraph.co.uk/news/worldnews/northamerica/usa/11284721/CIA-torture-report-enhanced-interrogation-helped-us-catch-Osama-bin-Laden.html