How about the French helping us to become independent of England?
Well, a lot has happened since that time. The French weren't doing it out of the goodness of their hearts. They were already enemies with England, so they would have been willing to do anything to hurt their enemy. Besides, the French weren't exactly our friends when they backed Maximilian in Mexico, so that cancels whatever help they gave us in the Revolutionary War. We also helped them in both World Wars, so it's not as if we owe them anything at this point.
How about helping us to defeat the Germans and Japanese, which if we all had lost, this would have presented us with a serious threat here in the States?
They were helping themselves more than they were helping "us." If anyone helped us, it was Russia who helped us far more than all the other European powers combined. Why would we treat Russia so shabbily while falling all over ourselves trying to kiss the backsides of other European powers? What do we owe Europe that we don't owe Russia, at least regarding defeating the Germans and the Japanese?
No, it is not "one-way". For example, the post-WWII Marshall Plan helped to stimulate manufacturing here in the States, thus helping to create us as being the world's number one superpower.
Manufacturing was stimulated in the U.S. by the war itself, as well as being the only major industrial power which wasn't in tatters at the end of the war. I still don't see how it's helped America for the long term, nor does it imply any obligation for a permanent commitment to Europe. I don't see that Europe has done much of anything to help Americans at all. Many Europeans often complain about American militarism, but they're they ones who created the need for American militarism. If Europeans would stop pressuring us and stop obligating us to have some sort of "commitment to Europe," then the US government would not be able to justify its military adventurism, and they would get no public support for such.
"No man is an island", and nowadays neither is any country an "island" unto itself. Isolationism, such as that which we took both prior to WWI and afterword, allowed the rise of fascism that led to WWII.
We were never "isolationist." "Isolationism" is what North Korea is now, or what Albania was during the Cold War. We were
neutral, not isolationist. There's a big difference that has to be noted.
Our relationships with most countries were friendly and cordial. We had ties of trade and commerce, as well cultural exchanges, free flow of communication/travel. We were never closed off to the world; the main difference was that we didn't play favorites between nations, and we didn't want any foreign entanglements or permanent alliances.
And really, I don't see why the US should be blamed for supposedly "allowing" the rise of fascism. If the Allies had stayed faithful to Wilson's 14 Points, instead of what they ended up with at Versailles, then the conditions leading to the rise of fascism would have been minimized. If only Britain and France would have agreed to "peace without annexations or indemnities," then so much turmoil which followed WW1 could have been avoided. But no, they just had to have their pound of flesh, didn't they?
Ironically, it was that same treaty which led to British and French control of former territories of the Ottoman Empire which are prominent hot spots in the news these days. They screwed that up, too.
History has shown that it would be a colossal mistake on our part to somehow think that we would be better off if we go it alone.
Go it alone against what? Prior to our permanent alliances with European nations, when/where did America have any real enemies to worry about? The only European power to invade American soil was England itself, but after the War of 1812, we both realized we didn't want to be enemies anymore. For the remainder of the 19th century and up until WW1, other than the Indian Wars and Civil War, the only wars we fought with outside powers were the Mexican War and the Spanish-American War, which was only limited to attacking Spanish colonies, not Spain itself.
We did our best to stay out of European wars, such as the Napoleonic Wars, the Crimean War, the Franco-Prussian War, etc. We didn't really need to get involved in those affairs. It was the same for the Russo-Japanese War, although we did serve as neutral mediator to help bring that war to an end. We even tried to stay out of WW1 at first, but a combination of factors led us to enter that war.
But it was our involvement in that war and the aftermath that left a bitter taste in Americans' mouths that may have further reinforced the idea that America would be far better off to stay out of European affairs. That was part of the reason we didn't ratify the Versailles Treaty or join the League of Nations.
But we can't be blamed for the rise of fascism in Europe, which was really just a more extreme version of the same malignant nationalism which had been pervading that continent for over a century or more. It's hard to play "what if" and hypothesize about what might have happened if the US joined the League of Nations and put more teeth into those trying to thwart German aggression.