They probably mean it as "they"=people in general. The implied subject could also be "I". It's a bit like if you said in English: "it is not recommended that...". The implied subject could be "people in general" or it could be "I" or "our organisation" etc. But the logical subject is left out because it's not important in context, the important thing is the recommendation.
It is just one of the possibilities. If the one you tried is not accepted, please flag it.
This choice sounds a bit awkward (to me) to be accepted. My immigrant grandparents would have said it this way but I'd put red ink all over that if one of my ESL tutees wrote that in an assignment.