They should not;
1. The posts were made prior to the employment request, therefore it shouldn't matter what they did before they were employed.
2. Social media today isn't taken as seriously as before, meaning that people can share and say many things as a joke, or out of fun; that doesn't automatically mean that they stand behind it or truly mean/desire it
3.Social media can be wrongly interpreted by the employer thus creating miscommunication and misleasion
4.Social media account could be old and/or hacked
