Yes but that just means they rushed him at times when he is more likely to win versus rushing every down, plus you do not know whether he is rushing or falling back whereas you know Watt is coming. I agree with your idea but there can be an explanation for it.
For that reason, at least for now I have him at 4: Donald (possibly best defender ever), Watt, and Bosa. Basically I give the nod to people who were defensive player of the year the past 2 years and also to possibly the best defender ever but outside of that give me Parsons all day every day.