It was a bad decision specifically because, as Harry himself articulates, he did not actually properly weight the pros and cons. It could have very well BEEN the right decision if he had spent more time evaluating it. But instead he made his decisions based on the assumption that his life had a plot.
I should clarify that I DON'T have any problem, from a literary or a reader perspective, with the decisions Harry made towards the end of Act 1. Eliezer put a lot of effort into setting up that finale so that it made sense in context, and had a huge emotional payoff. But I feel that that effort has now paid off in full. For me to get behind Harry making a new set of questionable decisions, I need more proper setup for it to feel right.
Granted, there are people who felt from the very beginning that Harry was psychotic and evil, and stopped rooting for him as soon as he dismissed Ron. And nothing will satisfy those people. And my own preference is just that - my own preference, and it may be that the story Eliezer set out to tell will not fully satisfy me either. I'm simply stating my own concerns.
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: