Ich management is very common. I do it myself. It's not a disease that kills that often. You don't need to do a bunch of crazy stuff to do it, and it doesn't mean your fish are immune or anything like that.
Velvet on the other hand can not be managed and will wipe your entire tank if it gets in the system within days. It's a good bit like ich, but has a life cycle of a few days rather than 2+ months. It often starts on the gills, where the fish has no slime coat protection and isn't noticable. Ich can also do that, but doesn't seem to happen as often.
Stress can be a trigger for herpes symptom, also other illness like a cold/flu is common to trigger it. So a good bit like fish in that way as well.
Which is why as I was saying before, I've never seen a single spot on my Naso, but then on my blue tang I see spots about once a month or so. Not a bunch of spots, between 1 and 3 normally. I never see spots on my mimic tang, however I do see him scratching. I do not see my sailfin scratching, but I see the occasional dot about once every 3 months. My sixline wrasse and my cleaner wrasse I see scratch occasionally, but never spots. Same goes for my diamond goby, but he also loves to get cleaned by the shrimp. All my other fish never show any symptoms, which is basically 4 cardinals, a watchman goby and a royal grammar.
Same tank, and every fish has it's own different response to the parasite. Because they are known to have different levels of slime coat. It's not a surprise that the blue tang shows the worst symptoms, it has the thinnest slime coat.
The white dots are not the actual parasite. The white spots is where their body is healing. Fish actually heal really really fast, so they heal up and it looks like the spot has "fallen off". The white dots are basically the end of the cycle.
The way it disappears is what fuels so many misconceptions. You have to understand the lifecycle.