WS for sure can't conduct any survey by its own and we all know why. Chinese airline was "Ordered" to buy C919 and we all know why. So I guess they made such claim by the method of "We all know why"?
As of C919, it does not means it can carry 190 people. The standard passenger number when C919 was designed to be 168. For future stretched version, I see 190 is not a problem. The A321 with dense seating configuration can go up to 244. I think C919 even with current length and dense configuration can go up to 190, but it is never in any discuss we can find online.