Probbly, but illnesses in cyclists are also closely related to fatigue. Cyclists stay very thin, and the greater the effort, the greater the risk of illness.Don't disagree with the point you're making, but the second half of Nys' season is not the best example - he got sick right before the Tour, started it before he'd really recovered, and it completely wrecked him to the extent where he had to end his season early.
Running the Tour de France has affected Nys's schedule. It would have been more difficult to do what he did in Poland after the Tour de France than last year, when he didn't do the Tour de France and was fresher for the season finale.