Proficiency is the Effect of taking such a Feat or Class.
If you gain Proficiency without taking a Feat that awards it to you (such as with Class Training or perhaps a Magic Item or Spell) then the prerequisites of the Feat that you didn't take don't matter in the slightest.
However, what the rules do say is that a character who is Proficient with an Armor or Shield Category counts as having that Feat. This means that whenever something asks "Do you have [Feat Name]?" you can say, "Yes," without actually having to qualify for, take, or implement that Feat in any way.
Effectively this is, "Counts as having [X]" even when you don't actually have [X] - just like "Counts as an Elf" works even though you don't gain any Elf racial features.
- Marty Lund
If you gain Proficiency without taking a Feat that awards it to you (such as with Class Training or perhaps a Magic Item or Spell) then the prerequisites of the Feat that you didn't take don't matter in the slightest.
However, what the rules do say is that a character who is Proficient with an Armor or Shield Category counts as having that Feat. This means that whenever something asks "Do you have [Feat Name]?" you can say, "Yes," without actually having to qualify for, take, or implement that Feat in any way.
Effectively this is, "Counts as having [X]" even when you don't actually have [X] - just like "Counts as an Elf" works even though you don't gain any Elf racial features.
- Marty Lund