The validity of this interview has to be put into doubt before you can even question the actual statements it poses. The U.S. intervention was a major milestone of the late war - it's sudden introduction in 1917 spurred on the German offensives of 1918 and almost brought the entire front to collapse.

So, no, these claims are not reliable nor realistic. Neither is the possibility that Churchill even made these claims. In 1936 he was still in the political wilderness. He never expressed these views around the time of war - and his stance post-1936 was resolutely pro-American - even making statesment to his son Randolph that to win the war was to drag the U.S. the war.

These claims have been made for two reasons - to give credibility to the statements by attaching the famous Churchill name to it, and to give some firepower to the isolationist cause that riddled both Congressional and popular opinion in the U.S.

These claims were singularly made in the New York Enquirer in 1936, as you state. This newspaper only existed for a few short years in the 1920s/1930s before being charged with sedition in 1944. (i.e. anti-war bias/strongly anti-intervention/opposed to the war.) It is now a tabloid paper still being published as The National Enquirer.

So it is a tabloid-like newspaper which has a isolationist bias. This immediatly casts suspicion on the interview. Let alone that the interviewer - William Griffin - was an out-of-touch editor who claimed that Britain should repay American war debts by handing over cruise ships. Yeah, even famed isolationist paper The Chicago Tribune didn't think Griffin was the full quid.

In 1942, Churchill ended up denying the statement in a 1942 statement to the New York Times. While Griffin was also being indicted for sedition, a libel cause he brought against Churchill for these denials was rejected, giving legal credibility to Churchill's denials and to the reliability of these singular claims.

So I wouldn't give anymore credibility to historical analysis most likely invented by an isolationist tabloid editor in an desperate effort to inspire anti-war sentiment in the States, and attempt to bring Churchill's credibility to a sensationalist weekly newspaper.

First of all, this is a terrible source, at least from the academic perspective. It is published by a press whose stated purpose is to promote a libertarian, anti-government view. I don't mean to say that those views don't belong in scholarship; what I am saying is that these type of sources are not reliable.

Secondly, the source doesn't say what you says it does. It is not Churchill making these arguments; it is the author, who then cites Churchill who had "berated" American involvement in the First World War. This is the full citation:

In an interview to the New York Enquirer, Churchill berated, in June 1936, the United States for having joined the Allies in 1917. These had secretly tried to reach a compromise peace which would have saved countless human lives and certainly would have prevented the rise of National Socialism and probably even of Communism in Russia. His interview was read aloud by an “isolationist” before Congress in September 1939. Yet such a compromise peace would have not fulfilled Wilson’s dream of making the world unsafe by democracy.

This is just anti-Wilson rambling nonsense. To be clear, none of these is a direct quote from Churchill. And note that the second sentence literally makes no sense. Then, Wilson's "dream of making the world unsafe by democracy" is just an attempt to belittle Wilson's actual stated goal of "making the world safe for democracy," and a rather childish one I would say. This is not academic, you can ignore it if you want, and that will be the opinion of any historian in the field other than those who work for institutions like the Ludwig von Mises Institute.

1. This is possible, but I've only seen it argued in articles, etc. that are pulling for the Churchill quote or misquote that you mentioned.

2. is unlikely, I think. Wilson's "Peace Without Victory" campaign and 14 Points were much more moderate than anything the other Allies were kicking around. If anything, you could probably argue the American involvement moderated the other Allies.

3. I don't see the connection between American involvement and National Socialism. But IF the other points are true and IF a compromise peace was established, it might have made life in Germany in the interwar period more bearable and made National Socialism less attractive.

4. This I don't really see at all, I'm not an expert in the Russian Revolution, but I've always read that it was pretty much separate from American involvement until they started supporting the Whites.

Sources:

"The American Political Tradition and the Men Who Made It" by Hofstadter for my Wilson claim.

The rest are more like arguments from silence I guess. I've read a good deal about WWI and I haven't seen any evidence presented about Churchill's possible argument.

Churchill, you can't be serious?

Points 1,3, and 4 are valid, but point 2 is a huge assumption.

Had the US not intervened, it's not unlikely Germany would have won the war. If Germany hadn't lost, then there wouldn't be National Socialism in Germany. Had the war ended earlier in a German victory, yes then the war would have been shorter. Had the German military remained in control then they would have intervened in the Russian Civil War and helped the whites, potentially changing the course of that war.

Of course, Churchill probably never said this as others pointed out. If the German empire remained intact, fascism and nationalist racism would have still popped up somewhere else. The assumption of a compromise peace is that the Entente losing the war wouldn't have been a game changer. 2 out of the 3 Central powers were outright dismantled after WW1, and the third was ruined. It's fully possible Italy, France, and Russia would have been devastated by a peace treaty. Or the war could just go on longer as Britain refuses to back down, or the war could have ended in a relatively equal peace as everyone gets sick of fighting.

Generally this kind of "What if?" history is a futile mental exercise, because you can't really know anything for sure. So it's not exactly the purview of the historian in a strict sense. If you like the mental exercise of alternate history, I'd recommend checking out the Kaiserreich mod for Darkest Hour, which includes this very turning point.