... Conventional wisdom: the idea that there was a tribe of red haired giants called "Si-te-cahs" was just a myth.
Paiute legends: we buried them in that cave over there
Guano dealer: excavates cave and finds mummified corpses that appear to have red hair
Conventional wisdom: .... well they didn't have red hair when they were alive. ...
The Si-te-cah example illustrates an important point - 'conventional wisdom' is conventional only by association with a particular group among whom it's consensually accepted.
When one is talking about something involving multiple groups it is important to specify which group it is among whom a particular claim or conclusion is conventionally / consensually held. In the case of the Si-te-cah affiliations associated with the Lovelock Cave excavations there are two groups I'll use for illustration - modern Paiutes vested in ancestral lore and archaeologists.
From The Archaeologists' Perspective ...
The initial conventional wisdom of the archaeologists had nothing to do with the Paiute legend of the Si-te-cah. It was simply this: "When cultural remains are discovered it is wise to conduct an orderly excavation to see what we can learn."
The triggering event was guano miners discovering a lot of human remains and artifacts while digging bat shit out of Lovelock Cave - much, if not most, of which was destroyed, lost or looted before any archaeologists were notified. The miners' discoveries were in 1911. Partial excavations and artifact collections were done in 1912, and more formal excavations were performed in 1924.
Besides an additional array of artifacts, multiple mummified corpses were discovered by the archaeologists in 1924 - deliberately / ritually interred feet beneath the cave's floor. Some bore traces of reddish hair remains. One of these was a male of unusual stature (6 ft. 6 in.). They also happened to discover a total of 3 purportedly human bones which had been cracked open as if their marrow had been extracted. To the extent stratigraphic analysis could be done after the top layers had already been disrupted / destroyed / removed all indications were that the cave had been used for a long time - perhaps only intermittently - by possibly multiple different groups occupying the area at one or another time.
The excavations turned up no evidence directly supporting the legend that all the Si-te-cahs had been killed by fire to end a climactic siege. Because the topmost layers of historical human relics and remains had already been lost or rendered FUBAR there's always the chance it was a matter of the evidence being obliterated.
The resulting conventional wisdom was that Lovelock Cave had served as a storage, ritual and / or habitation site for multiple groups over a long period of time. There was no comment about the one corpse's relatively tall stature. The reddish coloration on hair remains was attributed to chemical staining. The small set of cracked human bones suggestive of marrow extraction was hypothesized to be evidence of situational cannibalism during a period of famine.
From The Paiutes' Perspective ...
The initial conventional wisdom of traditionalist Paiutes is unclear in its details. The most solid elements traceable back to before the 20th century relate to a separate cultural / tribal group with whom the Paiutes had been in conflict and whom the Paiutes had progressively confined into living on or within Humboldt Lake's environs and eventually eradicated in place or forced to abandon the area.
Even the Paiute informants weren't consistent or clear about the alleged massacre of the Si-te-cahs. Some related that the victorious Paiutes didn't find any bodies inside the cave when they were finally able to inspect it.
The most interesting possible change in Paiute conventional wisdom (i.e., lore) relates to the fact that allusions to the legendary Si-te-cahs as being (a) 'giants'; (b) 'red-haired'; and (c) 'cannibals' cannot be traced back any farther than the early 20th century, when the lore was collected during the course of the Lovelock Cave investigations or separately reported later.
It would be very interesting to check whether any earlier ethnological documentation (e.g., from the Smithsonian's extensive ethnological collections of the late 19th century) can verify whether these allusions were part of the Paiute lore prior to the Lovelock Cave discoveries.
As to all the purported 'research' ... You can review all the gory details in the 1929 book written by the lead investigators from both the 1912 and 1924 archaeological digs:
Lovelock Cave
L. L. Loud and M. R. Harrington
https://archive.org/details/LovelockCaveLoudAndHarrington1929/mode/2up