Libertarians have no qualms with peer pressure to encourage you to act a certain way. Their problem is with the state using their monopoly on violence for that purpose. Boycotting Grubhub, or offering to poach their employees with quick hiring turnaround, are both fair game.
So where were you when HN users had to reach for their fainting couches because people encouraged disassociating from/boycotting Thiel and his business ventures?