Hi Marley,
The truth is, so many bodily stuff is 'gross'. I won't say it 'out loud' but there are many, many, many things in a human body I dislike more than fungus and would rather not see, but asking people with such problems to cover themselves -especially in the summer months- so that I don't have to see it is not nice (I'm not talking about you, specifically, but in general). I did feel a tad offended on behalf of some people I know with the fungus problem, and I can see I was not the only one.
Yes, fungus might be gross. Cellulite too. And zits. And stretch marks. And scars. And any dermatological problem. I think if I say zits are 'gross', a person with facial acne might understand I'm saying he/she is 'gross'. Zits do cover their faces, after all.