"I don't have much to gain from hanging out with Hagrid" and "I don't care about Hagrid's well-being" are radically different statements, and the former doesn't imply the latter.
"I remember Mr. Hagrid holding you when you were a baby," she said. "I think he would be very happy to know."
At the moment, Hagrid probably has zero friends, as I imagine he's too intimidated by Dumbledore to think of him as a friend instead of a father-figure/employer/crazy old wizard, and I doubt Ron would have befriended him without Harry as a bridge.* The amount of effort Harry has to expend to brighten up Hagrid's life is rather low.
Harry is being seduced by Quirrel, and the more friends he has, the harder that will be for Quirrel. But Harry is cutting out everyone he can besides Quirrel, Hermione, and Draco. That's not a recipe for staying good.
Harry is acting cold but not evil.
When it comes to Hagrid, yes. Combined with the rest of the situation, Harry is definitely acting evil. What's his something to protect? His hubris. Or, possibly, the three seducers he's surrounded himself with. Not the simple people he can't stand to even share a meal with.
How is that not a recipe for evil? What would he have to do to convince you that he's on the road to hell? He's definitely got the good intentions.
*Further research suggests the Weasley twins, at least, were friendly with Hagrid.
But Harry is cutting out everyone he can besides Quirrel, Hermione, and Draco.
What about Neville? They seem to spend serious time together and have a strong connection. Hopefully this will be more apparent in the future (a la chapter 67)
Maybe even the Weasley twins? With the new chapters he may even be approaching Cedric Diggory--though it could be more of a cameo.
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: