Respeccing doesn't have anything to do with the "choices must have consequences" game design philosophy. The latter refers to narrative consequences, which isn't affected by the mechanical choices of character build (aside from maybe skill points, but that's all). Taking a talent that lets you engage one additional enemy at a time instead of a talent that lets you do extra damage helps flesh out your character build and says something about the character (i.e. that he is more focused on protecting his allies than being a butcher on the battlefield), but it doesn't have any narrative consequence in the game world beyond that. Narratively, you're not making any immutable, long-term decisions that impact the game world and the characters and factions that populate it. If you anger one in-game faction or character, that has interesting consequences later on. If you make a poor choice in choosing talents or spells that you will never use later or don't understand how they work, the only long-term consequence is that the game will be less fun because your character is crappier than it should be at that level. Mechanical choices are not part of the narrative; they are the meta-game.
No one is asking for an option to go back and undo a dialogue decision to help one in-game faction at the expense of another--that's the kind of choice that should have a long-term consequence on the narrative. Instead, people want to have the ability to respec so that they can play the type of character they want to play throughout the entire game, even if 1) their preferred gameplay style changes over time (e.g. wanting to play a heavy damage dealer instead of a tank), or 2) they realize that a certain mechanical choice freely given at level-up wasn't designed well or just doesn't work like they thought it did (not just from poor design, but also just because they player doesn't perfectly understand the system and is now stuck with a talent that might actually be useless for their purposes). Just because a character chooses to specialize in rapiers at level 3, why can't they decide at level 10 that rapiers are for sissies and that they should specialize in spears instead? There's no narrative reason, and in terms of gameplay it just makes sense to let people modify their mechanical choices if something with their character build isn't working like they had hoped.
4th edition D&D even has core rules built in for retraining at level up: you can drop one choice made at a previous level (either an ability, feat, or skill training) and instead choose a different one of that same level. It has restrictions in place to prevent you from rebuilding your character from scratch whenever you want, but it gives you the opportunity to try out interesting choices instead of either only picking the "obvious" choices or taking a risky option that ends up crippling your character for the entire time you play in the campaign. Even without such rules built in, you'd have to be a pretty stubborn, viking hat-style DM to not make concessions for a player who says, "Dude, we're level 10 and I've never used that talent I picked at level 1. Can I just replace it with something else?" I've even had DMs who would let players change their character's class in the middle of a campaign because they wanted to play something else. In a computer RPG, the only option is to let people respec or force them to start over from the very beginning of these epic 60-hour role-playing bonanzas any time they aren't satisfied with a mechanical choice they made tens of hours ago.