Myself, as a percussionist will side with my section. We do have all the rhythm and we are really the heart of the band. We also have to be very skilled with what we do. In marching band we have to march correctly while beating either the bass drum, snare drum or the tenors. We have to focus with our arms and legs, let alone carrying several pounds on our shoulders. (sorry sousaphone) We are awesome.
As a trumpet player, I will side with the brass section. While drums may be the heartbeat of the band, brass is the voice. Without the brass section the band would be like a mute singer. Without their voice, they're just a heartbeat and no longer a musician. The point of a marching band is to play songs. The key to a song is the melody, which the brass section carries. The melody is what people hear, and it is what they relate to. It is what makes the audience perk up their ears and enjoy the music. Because the audience doesn't want to hear a beat. They want to hear a song.
Can you imagine what your band would sound like without the percussionists? It would sound empty. Without the percussion section the whole band would have no rhythm. My band tested this and the whole band was off tempo even with the drum majors conducting. Then we took out the brass and the woodwinds and percussion played fine. Same with the woodwinds gone. Therefore the percussion section is more important than any other section.
The reason the percussion can play fine without the rest of the band is because there parts are simple and one dimensional. Your logic is flawed. Just because percussion can play by themselves the easiest doesn't make them the most important section in the band. When you remove the brass section you lose the actual song. All drum parts sound essentially the same. Brass parts are widely varied. The sound of the horns is what differentiates one song from another.
Further, in a marching band, the drum section is normally the worst section of the band. As a rule, drummers are ignorant of the finer points of music, especially when it comes to dynamics. The drummers lack of musicality forces the winds to play over the drums, which strains the entire bands sound. Without the drum section, bands could have a much greater focus on the subtleties of the music, dynamics and tone. The drum section lessens the quality of the entire band.
It might just be your percussion section because everyone loves our percussion section. I think that you have a misunderstanding of percussionists. I also play piano, guitar, bass guitar, trumpet, saxophone and violin. Your thought of percussionists not being musically talented is wrong.
Your argument lacked any clear support as to why the percussion section is most important in the band. That is because there is no evidence, because that claim is untrue. A drum section is an auxiliary group to the band, whose overall importance is somewhat negligible. The brass/wind's section plays the songs. If not to play songs, what is the purpose of the band.