You know, the mere fact that there's as much disagreement as there is is a rather solid endorsement of leaving it free choice. The AI needs to understand when it's advantageous to build an OFM and when it's not (and no matter what the detractors say, sometimes it's definitely not). Forcing fleeting upon it in all circumstances doesn't solve anything.
If you look at the thread there's strong agreement that orbital fleeting should be automatic. The people who disagree seem to be arguing either that A) lack of orbital fleeting is an advantage to the HUMAN player, which misses the point or

the AI should be seriously improved instead, which likely isn't going to happen even if it *could*.
Serious AI improvement in this aspect is a pipe dream, because what you're basically saying is "the AI should become a lot better at manouvering, actively intercepting human players, and knowing precisely when to use the cheeseball tactic of ultra-cheap delaying ships to allow mobile reinforcements to arrive". Problem is that in computer games in general - not just Galciv 2 - AIs are just not as good as human players at sneaky manouvers. It is REALLY HARD to make AIs good at this. How many games have you played where the AI can barely pathfind its way across a map? I've played lots.
That's why the game *needs* to support a decent static defense. Because the human player is always going to be able to outmanouver the AI, so when that happens the AI had better have a half decent ability to defend its planets. And the orbital fleet manager isn't good enough because you need mid-game technology to get it and at least a midway-developed planet to reasonably build it, and even then only the AI and the new human player needs it. So for the AI it's a handicap and for the new human player it's a source of sheer aggravation because they don't know they need it and don't understand why they can't seem to properly defend their worlds in this game the same way they do in every single other 4x game they've ever played.
(Sometimes I despair at the utter lack of concern people here give to whether things in this game should actually make *sense*, and especially whether things should be avoided if they're completely counterintuitive to new players).