Maybe I can end this by defining condition, currently being used as a noun:
The state of something, with regard to appearance, quality and working order.
Therefore a mental condition is the working order of someone's mentality. Because people are genuinely bothered by these noises, their mental working order (aka mental condition) is that they get bothered and/or angry.
The only thing you have to so from there is giving such condition a name, such as: misophonia