Perhaps I haven’t explained it properly. Maybe if my name was Yann Geysir you’d be all ears :)
Yann Hafner wrote about article 8 in one of his papers on eligibility from June 2010
(extracted from the french version)
[Rz 47] The second nationality can be derived from a dual nationality, a nationality which allows a player to represent more than one country or naturalization. In the case of naturalization, it must have been acquired before playing for all or part of an international match of any age category, failing that, article 7 will apply and the player will have to comply with stricter rules.
Actually, Yann is not fully kosher here, if a player fails to satisfy that single important condition in article 8, a timely acquisition of that naturalized citizenship, no compliance with article 7 will rescue the application to change associations, because article 7 eligibility is bound by the strict terms in article 5 part 2.
An article 7 applicant is uncapped at any level. An article 8 applicant has already been capped and looking for an exemption from the conditions in article 5 part 2
But it's interesting that Yann clearly implies that if naturalisation was the source of the 2nd nationality, the timely fashion of its acquisition is enough to satisfy FIFA and if it was not obtained on time, he says (albeit erroneously) they will have to satisfy the stricter rules in article 7.
In a crucial part he agrees with me :), the terms of eligibility in article 8 are separate from articles 5 and 7 and are also less strict.
Why are the terms of article 7 stricter?
They are stricter because they regulate the integrity of the application of uncapped players to play for the country of their new citizenship. Those applicants have to be uncapped at any competitive level, because article 7 first refers to article 5 and the integrity of the change to a new country comes under greater scrutiny due to blatant exploitation of loopholes which challenged integrity.
Article 8 is for players who have already been capped at some level and who are applying to change association, as per their dual nationality.
There is a completely different criteria for them, much less strict.
An Irish citizen who was born to a naturalised Irish citizen outside Ireland, is exactly the type of dual nationality that can avail of article 8 to change associations, as long as he activated that citizenship before being capped at underage level for his country of birth.