I say otherwise.
While diseases or physiological disorder of various kind might present themselves every now and then depending on the care and situations, I find oncidiums (and not all oncidiums) particularly prone to leaf issues.
Hence, I don't deal with them any more. lol
I have hundreds of orhids and I do get sick plants but that happens on just a couple out of hundreds each year. and some lucky year, I have no problems at all.
Sickly plants just freaks me out because it worries me much. I spend too much time taking care of my plants and last thing I want is disease spreading in my collection and ruin them.
Early detection and removal is the key.
By the way, regarding to this specific issues of those raised bumpy green areas, I have seen them on some miltoniopsis and wildcat varieties.
My guess is either just some physiological disorder that does not harm the plant or work of virus.
I do not think it's a work of bacteria or fungi.
You don't need to cut them off.
When you see brown or black mushy rot that spread fast, then you know you have bacterial or fungal pathogen at work and you want to act fast.
Common leaf spotting, all by fungal organisms, do not seem to harm others while oncidiums tend to get them so easily.