I think going by consensus is the appeal to popularity. Its also appeal to authority when refering to scientists.
This is wrong. When citing science, this is not at all the same as appealing to popularity, that "everyone believes it, so it must be true". This is absolutely disingenuous on your part. Citing
experts in a technical field is what you should do, when you are not educated in that field yourself!
Using you're analogy, it would be like you talking to a computer
expert who says you have a virus on your computer, and telling them, "Well, that's your opinion. I believe it's an evil spirit, and God will cast it out through my prayers over my monitor. My opinion is just a valid as yours". That is how absurd this all is, equating the level of
expertise in these given fields to nothing more than "their opinion". Absurd.
Question. What is the role of
experts, and do they know more about things than you do in their given areas of expertise? Bonus question. Should you listen to them, take them seriously, or blow them off as not really knowing any better than you about these things?