I see all of this people complaining as if they're surprised about this when we've known for weeks that we'd be getting revisions of these chapters and it confuses me a little. But I suppose some people just don't keep up with Murata's twitter or the OPM discussion to hear the news.
And honestly while I get that this can be frustrating for people, as a writer myself I understand the feeling of wanting to go back and change something earlier in your story to reflect how it's shaped to be later on. For a lot of types of stories, we don't get to see this revision process because it's all done before the stories are released to us, hidden from view without the pressure of regular releases. But manga don't work that way and most manga artists don't get the chance to think too much of what happens later on or go back and revisit what they want in the pressure of new releases being required on a weekly or bi-weekly or monthly schedule. If one artist gets the chance to break the mould and actually work to improve their series and make it the best version it can be, I don't think it should be discouraged.
I don't know if this is happening because ONE hadn't thought that far into the webcomic before or if he just failed to communicate what would happen to Murata and then Murata felt he needed to change past chapters to reflect the recent webcomic developments, but either way it's not really that bad. We often think too much of the state of things while the manga is still being released, but remember that one day that will end and the manga will then remain unaltered. It might take ten years or more for the manga to complete (very possibly more), but once that happens the time during which OPM will live on as one complete story will be far longer than that and it is not surprising that Murata/ONE would like to deliver the best story they can in that regard. The weekly/bi-weekly/monthly release is ephemeral, but the complete product is forever. So, no Murata and ONE don't exist solely to satisfy your craving for new developments every two weeks, it is equally important to them that the story they create as a whole is good, too. If you would prefer to read a story whose writer has no passion for it, I'm sure you'll find plenty lifeless ones that get churned out every week though to satisfy you.
Of course I'm not saying that Murata/ONE should miss the forest for the tree while they continuously remake the same stuff, but let us not exaggerate the situation here. A couple revisions now and then does not mean much in the large scheme of things. You still get to enjoy your scheduled OPM like normal most of the time. So really everyone's just complaining because of a temporary inconvenience that will soon go away. Really Murata even said he'll work on the next (new) chapter immediately after finishing the revisions (which are now done as you can see), so we'll get it soon. If there ever was a time to complain that was when this "hiatus" started, but now it's over. So get over it.