Mussolini suffered a huge reputation hit by his association with Hitler, who he thought was a moron.
But on his own merits, he is no worse that leaders of great Britain, Belgium, Spain, or many other similar countries in that time or space.
But he chose poorly in WWII.
He chose to use Mustard Gas on Ethiopian civilians, that alone merited his eradication from the planet.
Even Adolf Hitler never used Mustard Gas in battle, having experienced the effects of it in WWI.
He wasn’t going to choose any other way, given the similarity in ideology and the “Roman Empire” outlook.
And “no worse”, seriously (excepting Belgium)? Too many people are sucked in by socialist historical revision these days.