This is interesting to me because I'm a degenerate "massive comment" guy. People have gotten mad at me for it before, I'll take a comment from them, break it down, address it portion by portion with citations, and then ask their thoughts. It's probably an obsessive level of engagement that people aren't really interested in, which is fair, but I don't know how else to get my point across in its totality.
Also there's some subset of users on this site who are rate limited, such as me. So for me that manifests in avoiding post for post conversations and more seeking to engage in an exchange of essays where I try to predict future points and address them, to save comments, which obviously results in long comments.
One suggestion from a fellow longwrite: Tweak that to “leave an opening for their optional reply” so that it’s okay if they don’t respond, so that you aren’t creating discomfort and pressure by the comment length, and you should see an easing both of pressure on yourself and on others. One of my most frequent longwrite sigs is “Reply optional as always” :)