As a conservative Independent, allow me to explain why so many conservatives either accept the Warren Commission's claims or just don't care about the case:
* Too many conspiracy advocates inject their ultra-left-wing politics into their writings, even though JFK would be a centrist Republican or a Joe Manchin Democrat if he were alive today. Kennedy ordered huge increases in defense spending, pushed for massive tax cuts (including for the rich), appointed numerous moderate and conservative federal judges, and insisted on fiscally responsible budgets.
* Too many conspiracy advocates--nearly all of them--call the Vietnam War "dishonorable," "unwinnable," "unnecessary," etc., when in fact the war was an honorable and winnable war whose goal was to keep 18 million people from falling under communist tyranny. Just because JFK may well have withdrawn U.S. combat troops from Vietnam in 1965 does not mean he would have stood back and done nothing if South Vietnam had begun to suffer serious defeats and appeared to be in danger of falling to the communists.
The Truth About the Vietnam War
https://sites.google.com/view/vietnamwartruth/home* Two recent, and very good, pro-conspiracy books that I recently read took cheap and needless shots at Donald Trump and at Trump voters. One of the books repeated liberal talking points about George Floyd's death, while saying nothing about how Floyd caused the police confrontation in the first place, about the fact that Floyd had numerous chances to avoid being pinned but refused to cooperate, about the fact that Floyd fiercely resisted arrest and kicked two of the officers in the process, about Floyd's long criminal record (including armed robbery), about the fact that the defense proved that Chauvin's knee was *not* on Floyd's neck but on his upper back (two prosecution witnesses admitted this under cross examination), about the fact that Floyd may well have died a few hours later because he had ingested nearly four times the lethal dosage of fentanyl, and about Floyd's work as a porn actor (in one movie he had sex with a girl young enough to be his daughter).
* Far too many conspiracy advocates use foul language in their writings and lectures, which is not only in poor taste but turns off many religious conservatives. In one JFK assassination conference that I recently watched, one of the speakers dropped the F-bomb twice and the S-word once, while two others used the S-word. This reinforces the impression that many conservatives have that only immoral, foul-mouthed leftists reject the Warren Commission's findings.
Based on my own experience working as a volunteer for the Trump campaign in 2016 and 2020, I would say that at least 20% of Trump voters believe that JFK was killed by a conspiracy. That's just my own experience. The percentage may be higher, but I seriously doubt that it's lower, based on the many chats I've had with fellow Trump voters.
But I can also tell you that many, many, many conservatives view JFK assassination conspiracy advocates as anti-American, immoral leftists, even though quite a few of them recognize that JFK was somewhat conservative on several issues (tax cuts, fiscal restraint, strong national defense, law and order, cracking down on organized crime, immigration, etc.).