Looking just at the combination of the words "conspiracy" &
"theory", it would seem to include theories that are supportable
by a cogent evidence based argument. But "conspiracy theory"
is idiomatic, referring to unsupported beliefs, eg, faked Moon
landings, Jewish space lasers, the stolen 2020 election.
Conspiracy theory - Wikipedia
Excerpted....
A
conspiracy theory is an explanation for an event or situation that invokes a
conspiracy by sinister and powerful groups, often political in motivation,
[3][4][5] when
other explanations are more probable.
[3][6][7] The term has a negative connotation, implying that the appeal to a conspiracy is based on prejudice or insufficient evidence.
[8] A conspiracy theory is not the same as a
conspiracy; instead, it refers to a hypothesized conspiracy with specific characteristics, such as an opposition to the mainstream consensus among those people (such as
scientists or
historians) who are qualified to evaluate its accuracy.
[9][10][11]