This theory means nothing, and is only a phrase you use when replying to some bullshit theory on a social media app, such as TikTok.
Example 1:
RageBaiter123: i love how we say girl when excited and man when we're sad
DumbFuck67 (replying to RageBaiter123): red car theory
John456 (replying to DumbFuck67): sproingle doinkle theory
Example 2:
SemptumRing2: donald trump is in the files.
DumbFuck68 (replying to SeptumRing2: septum ring theory
John457 (replying to DumbFuck68): sproingle doingle theory
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.