I don't understand why anyone would vote for a candidate who participates in an election process but is only willing to accept the result of the process if he/she wins the election. It was bad enough when Hillary Clinton delayed conceding defeat to Donald Trump back in 2016 but now vast numbers of (mainly) Republicans seem to think it's acceptable to deny their loss and blame some kind of incorrect process.
Clearly, only accepting the result if your side wins is appalling behaviour. But as to why people would vote for a candidate who does that? Well, let's suppose it was the other way round, and it was the Republicans who were respecting the electoral process and the Democrats who kept crying foul and telling lies about the elections whenever they lost. And imagine you're somewhat left-wing.
So your choice in this hypothetical situation comes down to... A Republican who opposes any action to combat climate change, wants to ban all abortion, opposes all gun control, and wants to do loads of other things you find appalling, but who respects the democratic process. OR A Democrat who will do exactly what you think is needed for the country, with the one exception that he/she keeps trying to undermine elections whenever he/she loses.
Who are you going to vote for in that situation? Difficult choice, isn't it! But if you reverse the politics, that is the kind of choice faced by someone in the US who has strong right-wing views and also respects democracy and is appalled by Trump's election lies.
Maybe that makes it understandable why some people might be horrified at Republican election denials, but choose to vote Republican anyway.