Should employers be able to fire workers based on what they post on social media?

Should employers be able to fire workers based on what they post on social media? Why or why not? 

Will be needing part one (P1- Thesis- topic sentences ) on Tuesday JUl 9th 2019 since corrections might be needed per instructor feedback. if no correction i will let you know ASAP so Part two (P2) can be done (P2- two body paragrahs). P-2 is due 07/14/19. part three (P3- complete essay) due 07/21/19. i will like to receive drafts before due dates and i will also wish for writer to follow all instructions in the paper.