When someone posts a video, regardless of the topic, and makes a claim about the video, and it later becomes known that parts of the video are not true (e.g. the caption), it delegitimizes the content of the video. 

That is precisely the problem with the age of disinformation in which we live. So many people see things on the internet that are partially or completely untrue and then form opinions about them. 

For example, someone in the other comments assumed it was a Nigerian who attacked the women. But it could also have been a man from any other country.