Individual scientists are people and they do what they wish. They have friends, enemies, biases, bad personality traits, and temper tantrums. Some may also believe in voodoo, karma, or reincarnation. But this is not part of science, these are just traits of the individual.
This is the same about rejecting something because the author is "not an expert". Individuals might do it, but it has no place in peer review or other form of official commentary.
Expertise is a good thing, it's because we encourage it that the world works as well as it does. We don't really have a meritocracy, but by moving scientific institutions towards judging, selecting, and hiring based on expertise, they've done better than in the past when there was more nepotism and favors at many research universities. Granting the benefit of the doubt to those who have proven themselves able to do the work is rational, to grant the benefit of the doubt to random people regarding their expertise is deeply foolish.
But fundamentally you're still conflating terms. Many people presented as experts by the academy, media and governments turn out on close inspection to not have actually proven themselves able to do the work! They are "experts" and "scientists" but not experts or scientists.