I think the "fans" in track and field exhibit an open hostility on individual performers you don't typically see in other domains. Unlike popular team sports like American football and association football (soccer) where there's a tribal mentality which feeds into how the leagues market the individual club brands and coinciding merchandise and ticket packages, track and field athletes are really just out there competing in their own interest. How many of you are going to parade around in a Cole Hocker or Clayton Murphy t-shirt in public, or at an actual track meet for that matter?
Nationalism does nothing for me due to my background, so I don't feel at all personally aggrieved if say, Spain or Germany or any other country really, beats the USA in any international domain, but perhaps that is what is happening with many track and field fans when athletes competing for their preferred county don't perform up to a certain level? However, given all the smack talk I see from people on here about people at all levels of the running pyramid... hobby joggers, high school athletes, college athletes, running vloggers, semi-professionals, and professionals, I think a lot of runners are bitter former also rans that maladaptively cope with their personal demons around running by diminishing the accomplishments of other and talking smack online.