I've always found their intentions to be more implicit than explicit—I think the thing about the Infinites is that they never outwardly state their goals, but everything they do suggests some kind of benevolent intention. Perhaps this isn't on the part of Murozond, but it certainly is on the part of most of them. Firstly, I think that the set of dungeons in which we face them are good evidence of their misguided good intentions—the Culling of Stratholme, the Escape from Durnholde, and the opening of the Dark Portal at the Black Morass are all great examples of events which had terrible results ... in the short-term. The Culling of Stratholme killed many innocents and created Arthas as we know him. The Escape from Durnholde, although technically heroic, did lead to many horrible wars down the line. The opening of the Dark Portal brought the Orcs to the world and started the First War. I think these all suggest that the Infinites may be doing this out of a sincere effort to make the world a better place.
What they do not realize is that time is not always as straightforward as it seems, and sometimes the butterfly effect changes things. If the Culling of Stratholme were stopped, we'd surely not see Arthas—but Archimonde could well find another summoner, and the world may be doomed to be brought low by the Legion later down the line without the Lich King to foil their plans. Similarly, without Arthas, Illidan would've never found the Skull of Gul'Dan, nor would it have been brought to Ashenvale by the Legion in the first place. Consequently, the long-term results would be horrible. If the Escape from Durnholde were stopped, of course Thrall would never be freed and the world would remain dominated by the Alliance, but what of Blackmoore's evil plans? Without Thrall, Blackmoore well could've taken over much of Lordaeron—we see that very event occur in one alternate timeline in the books! Without the Dark Portal opening, the Legion could've found another way in, or Deathwing could've destroyed the world later down the line for the Old Gods, or any number of unforeseeable events. Every action has consequences, and this is what the Infinites wouldn't understand. Their morality strikes me as very deontological—they're not as wise as the Bronze Dragonflight, who are keen enough to realize that the timeline must be preserved, because oftentimes the consequences of destabilization are worse. This is the characterization I have taken from their actions and why I'm so interested in them.
That, and their aesthetic is cool.