This sound belongs to the wider wave of goofy ahh sounds that spread through meme edits and short videos, where normal effects are pitched, stretched or paired with shocked reactions until they become the joke. The air raid siren is a familiar warning noise, but in this version its serious meaning is flipped for comedy, similar to how a panicked oh my god bro oh hell nah man reaction turns alarm into exaggeration. Creators keep reusing it because the siren is instantly recognisable and works even without context.