Disclaimer: I am a learner, not a native speaker.
Simply put, this particular part of the tutorial confuses the concept of "passive" (피동) with another concept, "causative" (사동).
To give you more details, I will try to discuss this question from the following three aspects: First, the conceptual difference between passive and causative. ...
I am a native Korean. Please forgive my English if there are any mistakes.
Let's look at the three examples that you've written.
The translation is correct. However, the subjects of these sentences are different between the Korean and the translated one.
'저' is not a subject, because '이/가' which marks the subject of a clause is located after '그것', '땀', '화'. '...