America was a split nation. Many vehemently opposed the war, but many also supported it just as enthusiastically. If you refused to get drafted and went to jail, you would definitely face shaming and ridicule from your country. There were youth whose parents and other family might see them as unpatriotic lawbreakers. They might have difficulty finding a job after getting out of jail. These fears were serious.

On the other hand, if one was drafted, they would not definitely become an infantry soldier facing the Vietcong eye to eye in the jungle. They might get any number of jobs in the military, some safer than others. Even if one did get a dangerous job, there was only a chance of being wounded or dying, whereas the negative effects of opposing the draft were almost definite.

And jail was not the only option. Somewhere around 30,000 or 40,000 draft evaders left to Canada.