I don't think that there's any canon answer for your question but the main difference between Voldemort's other horcruxes and Harry is that Harry was an unintended horcrux.
We know that Voldemort's soul split when he tried to kill baby Harry because it was highly unstable and that part of it jumped into Harry in a desperate attempt to save itself.
We also know that the process of creating a proper horcrux is very complex and it involves advanced dark magic.
That being said, we can safely assume that the soul fragment that went into Harry did not have the benefit of certain safeguards or abilities that the creator would otherwise implement.
We can also assume that Voldemort would never build horcruxes that would give people some of his powers so Harry's ability to speak parseltongue is yet another clue that he was not a fully functional horcrux.
I think that Voldemort's soul fragment was entangled with Harry's soul but was almost completely inert. It would "act up" when another part of Voldemort's soul would come in close proximity to it or would somehow connect to it.
The Harry Potter wiki entry on horcruxes states:
J. K. Rowling revealed in Pottermore that Prof. Quirinus Quirrell served as a temporary Horcrux when Voldemort's soul possessed his body during Harry Potter's first year at Hogwarts. A notable difference however is that the piece of soul within Quirrell was able to exist without its container, as it abandoned Quirrell and left him to die in the Underground Chambers. This is due to it being the "main" soul that serves as the awareness and consciousness of Voldemort's psyche.
I think that this implies that any other soul fragment other than the "main" one is not really self aware. We know that they can make some decisions but those are mostly driven by the survival instinct.
There are also inconsistencies in the powers and abilities different horcruxes have:
- Tom Riddle's diary has the ability to communicate with people and "feed" on their feelings to gain power and form.
- Salazar Slytherin's locket can influence feelings and read minds.
- We don't know much about Marvolo Gaunt's ring other than the fact that it was able to protect itself by means of a powerful curse.
- Hufflepuff's cup and Ravenclaw's diadem seemed rather passive until they were destroyed.
- We don't see any horcrux related behaviour or influences manifested by Nagini.
This also leads to the conclusion that any power or ability a horcrux has, other than those that come with the soul fragment, is imbued voluntarily by the creator.
Answer for @tls:
I meant to say that any soul fragment would have a survival instinct, or rather a survival reflex, and some very rudimentary sensory abilities but it wouldn't be able to actually do something of consequence unless the owner would give it such abilities. As we can see in the second book, Tom Riddle's diary is just an "artificial intelligence", wrapped around a soul fragment, that is "trained" to interact with people and "feed" it their energy or feelings, to the point where the soul fragment would be powerful enough to act on its own.
Because of the second book, most people think of horcruxes as potential Voldemorts, sleeping until something triggered them to return to life and full form.
In reality, the events of the second book are the result of the ingenuity and creativity that Tom Riddle put in the creation of the diary horcrux.
The sole purpose of your everyday horcrux is to act as an anchor for the "main" soul into this world. You can picture them as actual anchors tethered to the original soul. As long as at least one horcurx exists the soul cannot leave this world, no matter what happens to the body. So the truth is that, probably, for an anonymous wizard, more than one horcrux is just overkill. Seven horcruxes don't make you more immortal than just one.
Voldemort went to such great lengths to create and defend his horcruxes because he was a famous dark wizard and knew that people would go to great lengths to make him go away.
That is why he created such special and powerful items. Think about it:
- Tom's diary had the potential to create another Voldemort but was offered no obvious protection.
- Gaunt's ring didn't do much* but was protected by a very, very powerful curse.
- Slytherin's locket was able to use the people around it to protect itself (not unlike the One Ring from L.O.T.R. when you think about it) and was placed behind a myriad of defences that Voldemort himself put in place.
- Hufflepuff's cup didn't do much* but was protected by the Gringotts bank.
- Ravenclaw's diadem didn't do much* but was protected by the elusive and "clutterish" nature of the Room of Requirement.
- Nagini is a creature, so nobody would think of it as a horcrux, and it's always under the direct protection of the dark lord.
* as far as we know
The diversity of Voldemort's horcruxes shows us that he wanted to make sure that at least one of his "anchors" would survive thanks to its own protection, the protection of others or by just being forgotten or passing unnoticed.
Going back to the night he tried to murder baby Harry, three things happened then: his body was destroyed, part of his soul split and jumped into Harry without any of them being aware of it and his "main" soul survived (thanks to the "anchors") and fled the scene.
So, to finally answer your original question :), Voldemort had absolutely nothing to do with Harry becoming a horcrux, hence its benign nature.