Yes, they do it for growth and for some people the notion that they think they are "god's storm-troopers" is appealing.
I think your statement "some JWs are unloving and unchristian because they choose to shun their loved ones" is better to read JWs are unloving and unchristian because they choose to shun their loved ones based without knowing precisely what the individual is supposedly guilty of doing
I think the danger with that is that it may subtly promote the idea that it's OK if there is a reason they know about it and it moves the discussion into what are and what aren't valid reasons.
Personal relationships should always be the sole right of the individuals concerned.