A better, more accurate, statement would be:
"They do not cause or aggravate bleeding ulcers, as do NSAIDS."
Hope that helps.
DG
Actually folks still suffered bleeding ulcers with Cox-2 inhibitors. Their selling point was that they reduced the incidence of major GI bleeds from about 25% in folks still taking older NSAIDs to about 20%, IIRC. That's still a lot of emergency transfusions, emergency procedures and traditional open surgery avoided.