Is it necessary for a writer to write about the social or political events of his/her time?

The first film version of Invasion of the Body Snatchers was released in 1956, at the height of McCarthyist paranoia about Communism. Mary Shelley’s Frankenstein was written in the early 19^th Century, during the period of mass scientific, philosophical and political development known as the Enlightenment, and most obviously after the work of Luigi Galvani in the 1790s. What people want to write and consume as media often reflects in some way the social and political events of the time. 

Of course, it is not necessary to produce work based on these events, even in allegorical form. There are many writers who write personal things, whether they be emotional exorcisms or stories based on the principle “I like unicorns, I like glitter, I like mage wars, lets write something about that” or anything in between. There are writers who write really weird, experimental stuff which features puns in multiple languages and is probably best appreciated with some heavy-duty OTC painkillers in case of headaches.

Of course, it is impossible to not have any influences of the events of one’s time. Even if you were to spend most of the day in one’s room and write, much like Emily Dickinson, you will have some outside influences from communications to the view outside your window. It’s up to the writer as an individual whether they confront these influences directly in their work or not. 

(You probably will though. You, and by extension your writing, are shaped by the social and political events of your time. It’s just not necessary to put it in there deliberately – and in the case of some writers, they probably shouldn’t.)