Meh. It's sad, but the structure of the universe is probably such that one cannot become a leader of millions without being a villain.
Also, it relies on equating hard moral choices with villainy. A hard moral choice is making citizen A hungrier so citizen B doesn't starve. Villainy is robbing citizen A to enrich citizen B because you like B more.
I happen to think that it is an incorrect statement, and that, while leaders of millions will make mistakes, they need not necessarily be villainous.
To be clear, I am not claiming that Churchill's actions in Ireland, Iraq and India were merely mistakes - the worst of them, together with the attitudes that allegedly justified them, belong in the annals of infamy.
Yes, we can denounce villainy that occurs on the global stage. But in truth that's almost entirely virtue signaling. We look good, but there's no difference effected in the world.
Do something that makes a difference. Despising Churchill is useless, even if he deserved it (which is dubious).
This isn't true at all. The collective fiction that makes up civilization depends on this.
Saying you believe in free speech, even though free speech is a national policy decision, is not virtue signalling if enough people do it. Saying you're against racism isn't virtue signalling if that makes the community as a whole more loudly against racism.
If everyone becomes cynical and refuses to "virtue signal" as you pejoratively call it, it swings the door wide open to the government ignoring our rights since the people have collectively already decided to give up.
Perhaps it's more that those viewed as "good leaders" are simply the villains that were needed at that point in time. It's easy to villify almost anyone in retrospect, even if people at the time viewed those issues in much the same way.