You’re absolutely correct that “(anything)phobic” is not an appropriate term for bigotry. Being phobic is as much a choice people make as being gay is, and of all the various groups, classes, etc. the gay community ought to understand.
The issue you’ll run into is common sense, and it’s lack of being common ;). Good luck trying to get people to understand, accept, acknowledge, etc.
White rot fungus, use very diluted bleach (like 5%, a cup of bleach in a gallon of water.) or vinegar (either might alter the wood finish though…), wrap the arm of the chair in paper towels and keep them damp with it for like 30 minutes or so to let it soak into the substrate of the mold inside the wood, and it should just come off with a brush.
Don’t let it go everywhere when brushing it off because the more you spread the spores, the more mold you get.
A steamer will likely make it grow more. It’ll look like it’s working but it’ll grow back worse.