Earlier quoted context omitted.
Its simple, and I'll quote myself - "robots.txt isn't the law".
Quoting Cervisia : > robots.txt. This is not the law In Germany, it is the law. § 44b UrhG says (translated): (1) Text and data mining is the automated analysis of one or more digital or digitized works to obtain information, in particular about patterns, trends, and correlations. (2) Reproductions of lawfully accessible works for text and data mining are permitted. These reproductions must be deleted when they are n…
If what you're protecting with robots.txt isn't copyright-able, then you'll need to find another legal means.