As a fellow grammar geek, I have no use for grammar Nazis. Most of them, in my experience, may be described as "frequently wrong but never in doubt."
Sometimes the subject of the sentence needs to be the recipient of the action. "They were beating him" is not the same as "He was being beaten." It depends on whose experience is more important to your story.
Strunk & White provide a lot of rules, but more central to their little jewel of a book is a philosophy of written language. They say end with the preposition when the alternative is awkward or confusing.
Know the rules. Know when to break them. Them infinitives ain't gonna split themselves.