The 1960s saw a growing social division over the war in Viiet Nam. However many remained neutral. Some objected to this neutrality by saying, "You have already chosen if you do not make a choice".
Most people "choose" to reject Christ by simply being uninterested. There are some who actually do reject Christ intentionally, however, for most, failure to respond is more a result of not having much interest in truth.
Joh 18:37 Pilate therefore said unto him, Art thou a king then? Jesus answered, Thou sayest that I am a king. To this end was I born, and for this cause came I into the world, that I should bear witness unto the truth. Every one that is of the truth heareth my voice.