Ok here is my take on things.
I have searched the rulebook and nowhere in the rulebook does it say anywhere that a spell with range:touch must use melee touch attack for it to work on an ally.
Page 179 reads: Touch Attacks: Some attacks completely disregard armor, including shields and natural armor—the aggressor need only touch a foe for such an attack to take full effect. In these cases, the attacker makes a touch attack roll (either ranged or melee).
It talks about making a touch attach roll against a FOE. If you needed to roll a melee touch attack against an ally as well, it would have just probably read that the aggressor need only touch the target and have to make a successful melee touch attack against everyone, all of the time.
This does not make any sense to me though. Seriously, why would I have to roll a melee touch attack roll to cast guidance on an ally when you are not even in combat? I think some people just assume you make an attack because there is a reference to "willing" ally in the rulebook.
For example on page 213 of the core rulebook it reads: Touch: You must touch a creature or object to affect it. A touch spell that deals damage can score a critical hit just as a weapon can. A touch spell threatens a critical hit on a natural roll of 20 and deals double damage on a successful critical hit. Some touch spells allow you to touch multiple targets. You can touch up to 6 willing targets as part of the casting, but all targets of the spell must be touched in the same round that you finish casting the spell. If the spell allows you to touch targets over multiple rounds, touching 6 creatures is a fullround action.
I think the word willing might be in there because if the target was not willing then it would be an attack and you cannot make 6 attacks in one round. Having said that, it still does not say that you have to make a melee touch attack for spells that could target up to 6 willing targets.
To further clarify, page 185 reads: Touch Spells in Combat: Many spells have a range of touch. To use these spells, you cast the spell and then touch the subject. In the same round that you cast the spell, you may also touch (or attempt to touch) as a free action. You may take your move before casting the spell, after touching the target, or between casting the spell and touching the target. You can automatically touch one friend or use the spell on yourself, but to touch an opponent, you must succeed on an attack roll.
It does not say you make an attack and it automatically succeeds, it says you "automatically" touch one friend or yourself. It specifically says that you must succeed on attack roll to touch an opponent but it is automatic for a friend. It does not say that your melee touch attack automatically hits, it just says the touch is automatic. A friend cannot willing be hit, they can willingly forego a saving throw or give up a special resistance to magic (page 217) but cannot willing be hit by an attack. And so maybe the willing part might be confusing people. An attack is successful if the target attacking makes a successful hit. Nothing in the rulebook I could find says that a friend or ally could willingly be automatically hit by an attack.
The definition of Faith's Reach further corroborates this idea of not needing a melee touch attack by saying:
Whenever you cast a divine spell with a range of touch, you can instead cast the spell with a range of 30 feet. If the spell normally requires a melee touch attack, it instead requires a ranged touch attack.
If all spells with range: touch required a melee touch attack this power would read that every touch attack requires a ranged touch attack - period. This power implies that some melee touch attacks do not require a melee touch attack roll - which ones? the ones you cast on yourself or friends because of the definition from page 185, those attacks are automatic.
And so this is my take on things, posters please tear my analysis apart because I want to understand this as much as the op. Also please use references from the rulebook.
