Does this have anything to do specifically with claims of discrimination?

For example, people generally have a poor view of sportspeople who give excuses for their performance, even if the excuses are completely valid and documented. It is, nonetheless, viewed as not being a good sport.

What about how we rate someone who complains about the ingredients when they're being judged on the tastiness of the food?

There's also a quantitative aspect here: how bad is the handicap of discrimination, injury, or poor-quality food? If the discrimination is being beaten up on the way to a test and constantly heckled and interrupted during it, do people have the same viewpoint as if the discrimination is, say, a 20% reduction in partial credit for not-completely-correct answers? If the food problem is "I was forced to cook with moldy ingredients", do people have the same viewpoint as "these were cheap tomatoes from Safeway, not heirloom tomatoes from a farmer's market"?

One might argue that we should apply different rules for discrimination than a fan heckling you while serving, or a sprained shoulder while playing basketball, or trying to make pasta sauce out of mealy tomatoes. But that doesn't mean that this is how people work psychologically, and if any of this is going to be actionable in any way, we had probably better know the difference.