In this case you could just do this:
set(#firstReviewer,$scrape attribute($element offset(<class="shop2-review-attribution">,0),"innertext"),"Global")
add list to list(%reviewerSplit,$list from text(#firstReviewer," on "),"Delete","Global")
But if you grab the whole thing and want the date you could also use this regex:
set(#date,$find regular expression(#firstReviewer,"[A-Z][a-z]+\\s\\d+,\\s20[0-9]+"),"Global")