Because the people that want to tell the world "I AM NOT FULL OF RAGE I AM ACTUALLY LAUGHING AT EVERYTHING I AM A COOL DUDE" tend to be boomers or gen-x junior boomers that never stopped chasing the South Park "not caring makes you cool" dragon.
I'm probably the only sane person using them for what they mean: laughter. Guess I'll go back to ''Hahaha'', cause I never got used to ''lol'' or ''lmao''.