When one fills out a job application, its a contract. On that contract, you agree that everything you have written on it is true to the best of your knowledge.
Also..
Even though we have rights, we may voluntarily agree to limitations on those rights during work hours as a condition of employment. And in other cases, there are agreements in your employment contract that limit what you can do outside of work as well. Its spelled out in the employment contract. If one agrees to employment terms with tough requirements, then its nobodies fault but the employees if they lose their job because they broke the agreement.
for example - a common employment requirement is the employee 'must be bondable' - if you are or become unbondable because of a criminal record you gain outside of work, you lose your job.
Other jobs with a high visibility of its employees require proper decorum outside of the workplace. So, getting drunk and disorderly on weekends, or putting photos of yourself pole-dancing on Facebook may cost you your job.
-- another example may be working for a Catholic organization as a proud 'out there' atheist.