Re: I know not of these matters...
"Is there a valid reason for one to perform such "equality checks"?"
First, no privacy is violated unless the data is moved from the application to some other place, without the user intending it. These lawyers will have a very, very hard time proving this - mostly because it is very unlikely to happen. I will happily write code that does exactly what LinkedIn is being sued for, and have done so in the past - but if my manager or employer asked me to write code that does this and violates people's privacy, then absolutely no.
And yes, there are plenty of _good_ reasons to examine the clipboard. First, in iOS 14 (and everywhere else) it is absolutely required if you want to implement "Paste" into anything other than text views and text fields. Second, you want to know what's in there so you don't have for example a "Paste" button if there is stuff that you can't paste.
And then there's the fact that in Windows, Linux, MacOS, Android, and iOS up to 13.0, everyone does it. For good reasons.