I've no idea where those comments have come from and whether they're a true reflection on what Dzeko actually said but no City player should be saying anything to potential targets that would make them choose not to come here. Certainly not in the media. Sterling has said about how Joe Hart talked positively about the club, the fans and the facilities and that was a factor.
As with any job, if you know someone at another company you ask about what it's like to work there. If they say "you're probably better sticking put for a while" you might listen. Fortunately with De Bruyne he's got a couple of Belgian's at City probably strongly pulling him to the club. One being about the most influential Belgian in football and our club captain.