I have a torn opinion about long follow-on posts.
Mostly, I'd rather have them posted in their extensive glory. Saves me linking elsewhere--sometimes a bothersome or futile effort.
My page down button works very fast and well. Hasn't broken my finger, yet.
I think getting annoyed over such a small thing is indicative of a bigger problem.
I have no problem with long articles copied and pasted as a post IF they fit the theme of the original. Luther's view of predestination doesn't meet that criterion, imho.
I do think it breaks the flow of the conversation.
I do think that it is possible to comment on a distracting practice without being annoyed. Actually, one can be sort of "matter-of-fact" about it.