My ex of 2.5 years is on the apps after 2.5weeks and using my prompts

Why would he do this? He copied my prompt that I had when we met on the apps. Like my pickup line. Pretty specific one and somewhat regionally/ culturally dependent to where I am from.

The breakup was initiated by him but it was complicated and he was hysterical. Idk. I am also on the apps and odds are he saw me. But I am a bit angered and flabbergasted by this move.