[Springtime]

This form of argument was covered in Daniel J. Solove's ''I've got nothing to hide'' and Other Misunderstandings of Privacy (available to read online), which goes into some detail about how such analogies are rather easily countered since they're not based on actual examples (privacy 'dead bodies' so to speak) that demonstrate abuse/negative impacts.

In this case the analogy being made is that by accepting certain forms of say, government agency snooping, they should therefore be fine with you seeing their data at a whim. However people often see themselves as an irrelevant target to the government and/or that given the vast number of data being collected they would be a blip and less likely to be personally spied upon, so they reason themselves out of being concerned (or having any concern for others that may be impacted).

[dredmorbius]

Solove, "I've got nothing to hide": https://papers.ssrn.com/sol3/papers.cfm?abstract_id=998565

[Mirioron]

Even if they reason themselves out of this concern, if that data ever leaks then it will pretty much be like handing over your phone. It'll likely even come with years worth of data.

[justinclift]

Imagine, one of their future kids becomes famous/president/etc.

That parent's history will be leveraged if at all possible, whether they like it or not.