Because people likes and dislikes are different. There are simply people who want the OPTION to be able to reset perks.
Think of the reset perk as an option to change Diffuculty Level. There's a choice between Novice, Adept, Expert and Master, you have the OPTION to be able to choose which difficulty level you want at any given time.
this is a good point. clearly changing the difficulty in the middle of a battle (or the game) is a cheap tactic, but i've yet to hear a movement to get that option stricken from the game. respec isn't even really a debate; you either want the feature or not. trivial matters of opinion typically make for poor debates.
taking up resources: the truth is, they have multiple teams working on multiple aspects of the game. what one should say is, 'i want them working on features I want, not on features You want.'
the game has no choices or consequences, let's not delude ourselves. let's take it all the way. in fact, in light of all the changes they made i'm quite surprised a respec option didn't make it in.
respec doesn't hurt replay value. what hurts replay value is skyrim is not an rpg and the great majority of quests are boring, linear, poorly written, and of the 'do or don't do' nature; there's very little role playing at all in this game. the game lets you become head of all major guilds, the deciding factor in a poorly written civil war questline, the slayer of dragons with the soul of a dragon bestowed by the blessing of a deity, the savior of the known world, and people are worried about other players creating an unrealistically powerful character with a respec option? these same people should also petition to disallow mods.
the fact beth so encourages modding is proof to me they want everyone to be happy with their product and have the ability to tailor their experience to their exact tastes. if part of someone's tastes is a respec option, then so be it. (despite my criticisms of beth, i have great respect for them and what they are trying to achieve; modding is one example where they not only 'get it', but get it right).
lastly: it's quite foolish to make assumptions about another's moral character based on how they play a video game or what features they want in a video game. ad hominem attacks are a logistical phallacy reserved for the weak of intellect.