A parser that can't handle comments doesn't care about obeying the robots.txt in the first place.
# comments
// comments
<!-- comments -->
/* comments */
plain text lines as comments
TeX-markup
script tags
HTML
PHP code
Whatever this is: https://www.costablancaworld.com/robots.txt
search-engine specific directives (Yandex has a few strange ones)
That's an RTF file that was saved as a TXT (without removing formatting)...
Somebody screwed up and made their robots.txt in a rich-text editor like wordpad.