> [The reasoning behind] Modula-2's full upper-case reserved word syntax [is] to make language constructs consistent and stand out more
I suspect it’s just inherited from ALGOL 68, where you were allowed to use names that coincide with language keywords at the cost of using one of a number of “stropping” conventions[1] to distinguish one from the other: surround each keyword with apostrophes (whence the term) or precede it with a period (if you’re using a single-case character set), type keywords in uppercase (if you’re not), or typeset them in bold (if you’re writing a paper—recall the original ALGOL problem statement was “like pseudocode from our papers but executable”).
Not really, unless you're talking about Extended Pascal or the several dialects.
ISO Pascal as Wirth originally designed it, only was modern in the sense of being much easier than ALGOL to implement and master, as learning language.
Meanwhile Modula-2 was designed from the start to be a type safe systems programming language, based on Wirth's learnings with Mesa at Xerox PARC.
I suspect it’s just inherited from ALGOL 68, where you were allowed to use names that coincide with language keywords at the cost of using one of a number of “stropping” conventions[1] to distinguish one from the other: surround each keyword with apostrophes (whence the term) or precede it with a period (if you’re using a single-case character set), type keywords in uppercase (if you’re not), or typeset them in bold (if you’re writing a paper—recall the original ALGOL problem statement was “like pseudocode from our papers but executable”).
[1] https://en.wikipedia.org/wiki/Stropping_(syntax)