There's a nasty stereotype out there suggesting that Pop Punk artists lack talent. That's supposedly why they play similar melodies and try their damndest to assemble whatever they're playing in as uncomplicated a fashion as possible.
In an attempt to debunk this myth FI successfully flexes their musical muscle by shredding their way to respect. Just listen to 'Through The Fire and Flames' and tell me FI lacks talent.
Sure they mold these Metal songs into poppier renditions of themselves. Partially because Pop Punk is the sound the guys love, but primarily the Pop Punk style is due to the fact that a carbon copy cover defeats the purpose of doing a cover in the first place. If a person wanted the original they would listen to the original.
The bottom line is when it comes to the flashier parts of each track, FI more than demonstrates their skill and talent just as impressively as some of the most renown Metal bands in the business.
FI isn't looking for validation though, they're looking for a reason to rock out to a few songs they enjoy, and maybe garner a little respect while doing it.