He's heavy-handedly manipulating someone for their own good, in a way that increases his own power and makes him feel superior. He's treating someone who should be a peer like a trainable dog.
If you accept that it's for their own good - and if it does result in their own good - then shouldn't that outweigh the heavy-handedness? But Hermione told him not to do that kind of thing at all, instead of "be less heavy-handed next time".
As for making him feel superior? Harry already feels vastly superior to someone like Lesath, as well as mostly everyone else apart from Hermione. I don't think giving him a few 'orders for his own good' would change anything there.
And he can't treat Lesath like a peer, for the simple reason that Lesath wouldn'...
Update: Discussion has moved on to a new thread.
After 61 chapters of Harry Potter and the Methods of Rationality and 5 discussion threads with over 500 comments each, HPMOR discussion has graduated from the main page and moved into the Less Wrong discussion section (which seems like a more appropriate location). You can post all of your insights, speculation, and, well, discussion about Eliezer Yudkowsky's Harry Potter fanfic here.
Previous threads are available under the harry_potter tag on the main page (or: one, two, three, four, five); this and future threads will be found under the discussion section tag (since there is a separate tag system for the discussion section). See also the author page for (almost) all things HPMOR, and AdeleneDawner's Author's Notes archive for one thing that the author page is missing.
As a reminder, it's useful to indicate at the start of your comment which chapter you are commenting on. Time passes but your comment stays the same.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: