Why do they call it that?

Why do ppl call mufflers as mufflers when now they do everything but muffle the sound…in which the contrary happens

OHH the muffel the sound. i just ran my sr just from the turbo elbow, cuz im putting a flex pipe in. much louder like 10x louder

They’re called mufflers because they muffle the sound. They do not ever make the sound louder.

What the hell?