She came on the No 1 bus around the New Kent Road with her toddler already having quite a tantrum. She dragged him on by his right arm, the overstretched sleeve giving the appearance of seemingly impossible elasticity; an angry, screaming, human pendulum. The rest of the passengers allowed themselves a brief, collective "oh crap" roll of the eyes and went back to their mobile phones.

She tried the standard repertoire from cajole to threaten, but the little boy wouldn't compromise. Whatever bag of extruded snack had been put away in her bag had become the single most important thing in the entire world. Finally, she pointed at me, leaned over and said: "Stop it, or I'll call the terrorist."

I don't know if she noticed the tiny, silent exhalation of gasp that escaped my lips. She looked at me, shrugged and winked conspiratorially, as if to say, "I know you're not, really, but needs must." Several people looked over at me, this olive-skinned man with a beard and a satchel; some shocked, others suspicious.

I got off at the next stop – not my stop – sat down under the bus shelter and tried to process what had just happened. As I replayed the incident in my head, a thousand sharp answers swam to shore. A thousand more have been suggested to me since. "You should have said … " But in that moment, I came up empty. As an actor I am used to people making superficial judgments based on my appearance. I know she meant no harm, of course, but the fear in her child's eyes affected me deeply. I was the monster under the bed.

I have been rehearsing for a play for some weeks now. I am playing Socrates this month in a modern retelling of The Clouds by Aristophanes. I agreed with the director that a big bushy beard would be right for the character. It didn't occur to me that, in the wake of the horrific incident in Woolwich, this would transform me into what Nick Robinson might describe as "of Muslim appearance".

And yet this is seemingly the world in which I exist today. News channels' 24-hour, binary, voyeuristic view of the world is the only message being shoved down our throat, like aspirin, every hour on the hour. Interviewing a traumatised Oklahoma teacher a day after the tornado – immobilised in a hospital bed, the camera shoved so close to her tear-stained face, I had to look away – is not only permitted, but expected. The porn of human misery. The caricatured shorthand for hero, villain, terrorist, freedom fighter, friend, enemy, good and bad has been so firmly established that it has replaced the truth.

In the play I'm doing, Socrates relays the parable of the prisoners in the cave recounted by Plato in The Republic. He tells of captives in a deep cave, chained in such a way that all they have seen their entire lives are the monstrous shadows on the back wall, made by people passing in front of the fire behind them. They have come to accept this world of shadows as reality. Once freed, they are unable to cope with the world outside. It is too bright and sharp; they are convinced it is an illusion. They beg to be taken back to the cave and put back in their chains.

Our flat-screen television sets have replaced the wall of the cave. Everything else remains unchanged. Commentators despair about the rise of far-right politics in Europe, but that is merely the symptom of a more general affliction. The combination of economic hardship, ideology (whether religious or political) acting as a proxy for critical inquiry and personal responsibility and the simplified world view being offered up by visual media, is a very dangerous one. Acts of violence in our streets, English Defence League rallies, Golden Dawn MPs and firebombed mosques are the natural consequence of that perfect storm.

However, there is cause to be grateful, too. These attitudes are not newly created; they have lurked under the surface for a long time. In this environment of fear and suspicion, of strivers and shirkers, of new bogeymen, they are expressed rather than suppressed. This is preferable in many ways. Once out in the open, they can be fought and defeated, as they always have been. "The sun doesn't always shine", says Socrates. "Sometimes there are dark clouds that bring rain and gloom. At times like these, it is easier to see. We are not misled by the shine on things."

It's a difficult time to be a foreigner anywhere and look it. The crime? Having a beard. The punishment? Public humiliation or worse. I will shave as soon as my engagement is over and feel peculiarly guilty for doing it. I will deal with the suspicious glances at my satchel in the meantime. I will never cease to hope you might turn around from your television screen and see me, instead of just my shadow.