|Darksol the Painbringer|
If a feat or special ability or any other combat rule says that it's a free action to use it, but you may only take that free action before or after another action (but not during), then this is not trumped by the general rule that lets you use it during another action. Such a priority order is not sane, as it renders the specific limitation inoperable.
The only possible, logical interpretation of this is 'specific beats general'. You might have heard this phrase before.
In context, the general rule (that you may take free action during other actions) is trumped by the specific rule (you may only deliver the touch attack in the three ways described).
As for PF adding the free action phrase meaning that PF deliberately changed how it works, the if they deliberately wanted to allow touch attacks to be delivered during other actions, then they would have taken out the sentence which meant that you could not do that.
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.
Show me where in that paragraph the word "only" is. And I'll give you the answer: You can't. Because it's not there.
If you're going to say that there are limiting factors, show language that implies such. You have no case otherwise.