Why is it TO to use Animate Dead?
Using animate dead by itself is not TO. Assuming you can easily find the exact creature you need, kill it, and then all the needed maintenance whitout problem is a lot more questionable. Zombies in particular don't heal naturaly (and the adept doesn't have inflict spells), slow you down, can be easily worn out by afar (in particular because they have zero stealth so they'll also warn everybody something dangerous is aproaching).
This is, would you allow a sorceror 8 to start a game with any combination of 32 monster followers that aren't immune to mind-affecting because he could theoretically have Charm Monster'd them all over 8 days and then keep renewing the charms?
Would you allow an evil cleric to start with a small army of Paragon 1 HD skeletons because he could've theoreticaly rebuked them? (as paragon template greatly improves combat stats but not turn resistance)
Adepts may have a lot of spells, but they don't have Call Hydra/giant/creature that's lovely to animate dead. Such creatures also have no sell price. They may not even exist at all in the campaign area in question. Assuming they're right there for the picking is indeed kinda TO.