Right, I don't think I've ever actually seen anybody make the "nothing to hide" argument. Maybe it was used more commonly in the past, but I only ever see people pre-emptively attack it without prompting. It seems to be a special case of a straw-man argument: a no-man argument. It's not the only such example, but it seems to appear without fail in the top comments in any discussion of privacy issues.
I found somebody making this argument just the other day on Hacker News in regard to license plate tracking.
https://news.ycombinator.com/item?id=46250556
> In practice I'm not even getting "tracked". No one is likely to be looking up my license plate and looking at my movements, because I don't do anything that would warrant that kind of attention
People around me make the nothing to hide argument all the time
It’s the obvious response to what seems like paranoia to the uneducated.
I have had many people use it when I try to either push for a private option ("please message me on Signal") or explain why I won't use a service.