Why do people think that the US won WW2 in Europe?

This also has a personal bias as I want the US to be remembered and not the UK who I think has done so much damage around the world pre WW2 in the name of colonialism including my home country.

The US still did however a lot to help.

That's not about US involvement, just your specific argument. Coming form Eastern Europe, we were liberated by Soviet army, Americans never touched our soil. But it was a brutal liberation, and what came afterwards was even worse.

Russians bled the most, killed the most. They wouldn't probably win if left on their own though for reasons stated by others. And that's purely Europe. Add Pacific and rest of the world and the role of US is undeniable. How difficult is it to accept that there is no single state who can claim the throne, only a joint force.

More interesting question for me is, if Japanese wouldn't do Pearl Harbor, how long it would take US to engage with Nazi Germany. Maybe far too long, US wasn't very keen to start open war. Maybe a critical window would be missed and invasion could be a failure.

You had systematic mass rapes on a bewildering scale. As in, every single female from city X was raped. See this article: "They raped very german woman from age 8 to 80" (https://www.theguardian.com/books/2002/may/01/news.features1...).

And it was not just German women. Similar things happened in Poland, Czechoslovakia, Hungary, Romania (http://www.globeatwar.com/article/red-armys-rape-europe) These reports would filter into diplomats in the West and they were so shocking no one believed it at first, and it was downplayed in the West but citizens from these countries remember. In addition to the scale ("almost no woman in Hungary was spared") is the blindness of the attacks. Everyone was a target. Especially shocking were the rapes of emaciated concentration camp survivors -- who had just been liberated by the Red Army! Often after the rape the women were shot and many committed suicides. Russian prisoners freed from German PoW camps were raped by Red Army units they encountered as they made their way back to Russia.

There was also extensive looting -- organized, systematic looting of people's household treasures, watches, clothes, shoes, etc. Soldiers breaking into homes, raping the women, stealing any currency or valuables. Then moving onto the next home. Block by block, city by city, across all europe. The native population quickly learned it was not safe to leave your home wearing a watch.

And of course that was followed by systematic political oppression, arrest of political enemies or those who were "tainted" by the West, including ordinary soldiers or aviators who committed the crime of flying with the RAF or with free French forces (https://www.wingsinexile.co.uk/clanky/return-communist-perse...) -- these were all jailed, de-personed, and hounded by authorities for the rest of their lives as being politically tainted. Remember some of these were national heroes. And that was followed by a series of coups in which the communist parties assassinated their opponents and seized power.

Bottom line, Eastern Europe has very mixed feelings about being "liberated" by the USSR, whereas Western Europe has much more positive memories of being liberated by the West, and so it's more a matter of one side celebrating while the other would prefer to not remember those events at all.