Leaving company after 3 days of joining

Hello, I started working with a media organisation. Within 3 days of joing the company, I realised they are working with a vicious agenda which aims to report stories in a manner which is provocative for the sake of likes and shares. The work environment was also uncomfortable for me as it went against my basic ethical and journalistic principle. I decided to inform my superiors after the 3rd day of work and I wish to leave the company. The HR despite my disagreement wants me to serve a month notice period or submit basic salary of one month to them. I don't need any experience/relieving letter from them. My only concern is to return the laptop they had issued to me for work purpose. What am I supposed to do in a situation like this? I don't wish to give them my hard earned money while I have not earned a single penny from that organisation. Also when I read the company policies regarding separation, it said that notice period doesn't apply to any employee who is in probation and their recruitment policy clearly says that all employees are in probation for 6 months from the date of joining post which the appointment letter would be issued. What am I supposed to do?