I know that Iron Giant attacks are considered WSs or JA or something.

My question is "Why?"

Why are their melee attacks considered whatever they are? It makes procing near impossible. They, themselves aren't that gripe-worthy, I can deal with the way the mobs are, I just don't see the point nor any logic behind this. They're deadly and challenging alone, the fact that you can't proc while they are meleeing is annoying and frankly stupid. Shinryu, IIRC, is the same way. Shinryu is the final boss of Abyssea, of course he's gonna be trouble in any way possible. But why Iron Giants?