Well you can but people are just going to think you are a Sum 41 cover band. It just seems like the Major key does not translate so well on electric guitar.
Simple answer? Because humans make symbols. Because we associate the minor mode with all the things metal wants to stand for.
Long answer? (Ok, you asked for it—)
We’ve been conditioned by several centuries of Western tonal tradition to associate major mode with happiness, life, light, and positivity, and minor mode with sadness, death, darkness, and despair. We hear Phrygian cadences as “happy endings.” If a major theme is restated in minor it means things have taken a turn for the tragic.
(Disclaimer: Even today exceptions are not hard to find. Pharrell Williams’ effervescent hit literally titled “Happy” is in minor. The tear-jerking (arguably maudlin) “Driver’s License” is in major.)
But this “major happy, minor sad” expectation wasn’t always a given even in Western tradition, or in other music-cultures. I once heard a Hungarian folk tune in pentatonic minor and thought it the most haunting, achingly plaintive thing aid ever heard. I checked the lyrics and they’re something like “Merrily the farmer harvests his grain.” In late Renaissance practice, rather than “happy/sad,” there was an association of major with “hard” and minor with “soft” (in fact, that’s still what they’re called in German, dur/moll). Minor was for lutes in ladies’ bedchambers, and major was for partaaaays. D major, in particular, was the hardest of the hard. That was the key of trumpets and kettledrums, who were the original army bands. D major meant military might and warfare. Trumpeters were an elite profession, hired by kings, and jealously protective of their privilege. It was illegal for just any Joe Schmoe to play the trumpet. Some poor fool of a shawm player tried just sticking his shawm out his bedroom window and pretending to be a trumpeter in a tower, and the Trumpets’ Guild broke in and beat him to the point that he would never play anything again. D Major was the original key of badassery.
(Disclaimer: It’s not as if the “happy/sad” associations can’t be found back then. Yes, “Dido’s Lament” is in minor, and that’s basically the 17th century “Driver’s License.”)
So? So if major doesn’t “work” for metal it’s probably not because of anything physical about the instruments or anything universally physiological about humans. It’s just because we humans love to tie symbols to ideas, and love to make symbols out of musical elements.
Doesn't it just come down to definition? As a gross simplification, Metal (by definition) is a genre that sounds dark/sinister, and as such tends to gravitate away from the major key, which doesn't tend to be associated with those moods. https://en.wikipedia.org/wiki/Heavy_metal_music states "Traditional heavy metal tends to employ modal scales, in particular the Aeolian and Phrygian modes."
It's very common for certain genres to be associated strongly with certain harmonic patterns - just as it's common for certain genres to be associated with particular lyrical themes, or combinations of instrumentation, or rhythms....
It just seems like the Major key does not translate so well on electric guitar.
There's plenty of electric guitar music - e.g. in the many other genres of rock - that gets a lot closer to being major than your typical metal song does. However, there is some truth in the idea that rock music isn't archetypically associated with 'pure' major tonality. You quite often find a kind of hybrid major/minor/blues/mixolydian tonality that is more flexible and subjectively ambiguous than you get if you stay solidly on the diatonic notes of the major key.
people are just going to think you are a Sum 41 cover band
Well, there's nothing objectively wrong with Sum41, and IMHO there's nothing terribly wrong with the music in the example video you posted. Who knows, many might prefer it to the original tunes! It's just that it wouldn't usually be seen as Typical 'Metal'.
The idea that modes and scales evoke different emotions is an idea that goes back to ancient times.
Metal uses modes and scale appropriate for the emotions it wants to express. Minor and exotic modes tend to be the modes of choice for a lot of metal music.
You can flip the question around to understand how some things are not appropriate for certain moods. Why don't people play funeral dirges at weddings? Because it wouldn't fit the mood to evoke.
Also, keep in mind a lot of rock styles mix different tonal elements. A common thing is to play major chords in the rhythm parts, but play blues or minor inflected melodic elements over those major chords. Another example is bass lines from minor scales but the chords above those bass notes are harmonized with major chords. Pure diatonicism is not really the harmonic style of rock. Even in the music like Buddy Holly or The Beatles which so often is bright and up beat.
It isn't that the major mode doesn't work for electric guitar, it's that it is not the typical mode of choice for metal.