I agree wholeheartedly with you that losing players hurts in many ways. When I first commented on the topic of player departures ("defections"), I highlighted the need for the coaches to connect and re-connect with players that have already left it all on the field. That wasn't a slight against the coaches or players for that matter. But, just like in our personal lives it is good to cultivate and grow the relationship. Grady is a huge loss. Very huge. But, to me, losing any kid that strapped on a helmet last year, is a huge loss because, by the end of the season chemistry was formed and the team developed an identity and trust among one another.
Some kids will leave and have left, but I wouldn't say that any of them have been a "cancer". "Cancerous" type players tend to stick around and cause chaos in the locker room/overstay their welcome and that doesn't appear to be the case with the kids that have departed so far.
I also agree that you can't miss what you never had so, to lose a recruit that hasn't played a down, is not too big a deal. Coaches leave schools for better offers so, I don't fault a kid for de-committing to be closer to home, go FBS, potential for more playing time, more scholly money, etc. I'm not going to pay his bills so, he doesn't owe me anything.