well, since they're programmed to simulate life perfectly, they can simulate crying somehow. couldn't tell you if they actually have tear reservoirs to hold a saline solution, or if they cry holographic tears or what...but they can.
The glitch race was created to simulate biological lifeforms (what lifeforms in particular we do not know), this results in them having a lot of functionality that dosen't make sense for a robot but allows them to more closely mimic biological life. This includes things like eating, using a toilet (i assume, since they have toilets), sleeping (another assumption based on them having beds) and crying (they have a crying emote).
