It's most likely that it wasn't a Leprechaun because it's more likely that Leprechauns don't exist. So that is the truth.
But it can't be confirmed that Leprechauns don't truly exist. By the same logic applied to evolution, I'm forced to accept that it may have been a Leprechaun that stole my wallet.
Because you're doomed as a scientist if you're going to explain things by God. But why should God to be the answer if they evolution theory looks so plausible?
No one even has to mention God. Scientists just feel paranoid that-that's what they'll be forced to acknowledge if evolution were designated as the junk-science that it is. It's possible to be an atheist and not believe in evolution.
Feeling compelled to carry on one theory that hasn't even been remotely proven just because you find the predominance of another particular one to be distasteful is not a credible outlook for a scientist to have. All it does is undermine their principles as scientists.