Certainly the description of the 'fan experience' in this article is accurate. For the fan, it is as if I myself have marched the show and been crowned champion, or made finals, or beaten this other corps, etc. Even if the 'winner' wins by 0.025, for example, it's still a 'win.' One group (or group of fans) is happy, and the others are not. It is kind of absurd that someone's subjective opinion of a performance determines my emotional reaction, but it's what happens, and only later, and then only for some, can rationality set in.
I can also see that the 'system' of drum corps competition can take a toll on performers, as it does in amateur and professional sports. People's bodies have been pushed often beyond endurance by the demands of modern drum corps staging and drill. Mental abuse in drum corps was more common in the past, but still happens. And as we know, reports of sexual abuse have been quashed for years for fear of damaging drum corps or a corps brand.
However, the article views fandom, and the performer's response to fan support, solely through the lens of a Marxist theory of capital's exploitation of labor. People go into, and stay in, competitive activities for all sorts of reasons - to prove themselves, for the experience of 'esprit de corps,' to hone expertise in their craft, as an extension of their education, etc. And people support organizations such as drum corps for a variety of reasons as well.
It seems that competition, and 'fandom,' can be experienced in many different ways. It is healthier when people are fans of the activity first and a certain corps second. I can appreciate the performances of each corps and not be as invested in my particular group's success and others' failure. I think that by and large this sort of support of the whole activity is more common in this era of drum corps, but I could be proven wrong.