It's difficult to say for certain without knowing the specific circumstances and personalities involved. However, there could be a few possible reasons why your ex is laughing at you for still liking him:
Emotional detachment: Your ex might have moved on from the relationship and no longer has the same feelings for you. They could find it amusing or surprising that you still have feelings for them while they have emotionally disconnected.
Coping mechanism: Sometimes, people use humor as a coping mechanism to deal with uncomfortable or awkward situations. Your ex may be using laughter to deflect their own emotions or to handle the situation in a lighthearted way.
Power and control: It's unfortunate, but some individuals may derive satisfaction from feeling like they have power and control over others' emotions. Laughing at your feelings could be a way for your ex to assert dominance and make themselves feel superior.
Misunderstanding or miscommunication: It's possible that your ex's laughter is not meant to be hurtful but rather stems from a misunderstanding of the situation or your feelings.
Regardless of the reasons behind your ex's behavior, it's essential to focus on your well-being and emotional health. If their actions are causing you distress, it may be best to distance yourself from the situation and seek support from friends, family, or a professional counselor to help you navigate your feelings and emotions. Remember that it's normal to have feelings after a breakup, and everyone heals at their own pace.