Given the sentence "Four people are sitting at a picnic bench eating while a fifth man stands next to the bench." is it true that "Four people are having a picnic while excluding their friend because he was a jerk."?
Step-by-step reasoning:
it is not possible to tell
Four people are sitting at a picnic bench eating while a fifth man stands next to the bench does not imply that they are having a picnic while excluding their friend because he was a jerk.

.

So, the answer is it is not possible to tell