Why don't modern Christians honor Christian rulers like Constantine and Charlemagne anymore?

WWI

Most Christians are laughably ignorant about the history of their religion

Except Eastern Orthodox
yes they are

What about Donald?

Modern 'Christians' don't believe in their religion.

Because, while its commonly toted that there is something like 1.6 billion christians on the planet, the actual number is much, much smaller. I am not trying to start a war over which denomination or sect is correct, but the fact of the matter is, that most "christians" nowadays are christian only in name. This is a plague in all groups. The vast majority of christians only go to church when it conveniences them (i.e. only christmas and easter), they only pray as a absolute last resort, they pick and choose what they want from the bible. Choosing only the "love your neighbor" bit, but anything that doesn't align with their own personal worldview, they choose to remain blissfully ignorant about. Again, this problem is rampant throughout all forms of christianity, whether it be catholic, orthodox, or protestant. So to answer your question, they don't honor them because they 1. dont know about them, or 2. dont care about them because what they taught, and stood for does not align with their own "personal christianity"

This is true. Even if you count only those people who hold to, say, the creeds of the first four ecumenical councils, the number of genuine Christians in the world shrinks drastically. Christianity is a doctrine, not just a life. When most of your followers can't tell you whether Jesus is God or whether they are sinners or whether Jesus was fully God and Man, died, descended into Hell, rose again and ascended to the right hand of the Father, that 1.6 billion number becomes fairly meaningless.

I'd argue the same goes for that OTHER fastest-growing religion: Islam. It has slightly less strict theological demands of its average follower (according to most sects: obviously Wahhabis and various Kharijite sects are stricter about theology), but I'm pretty sure if you look closely then the vast majority of Muslims are rank unbelievers.

This. This guy knows.

Broad statement as there are a few billion Christians in the world and no muppet on the internet can claim they think a certain way.

Because they were violent, and in the case of Constantine, paranoid maniacs who killed their own family members in their lust for power. They are not Christian and more like opportunists.

A minute of the population isn't historically illiterate tbqh

Good. The less christians are like muslims, the better.

Constantine was barely a christian even by contemporary standards and hardly a role model besides. He still worshipped pagan gods on the side (and was buried with pagan artifacts as well as christian ones), wasn't baptized until he died so that he could be a dick but still technically have all his sins cleansed upon his death, and killed his own wife and step-son.

He didn't really 'get' Christianity, in other words.

Constantine is literally a saint nigga.

Stop being retarded

and I'm sure the modern Christians who honor Constantine and Charlemagne are equally offended by OP's broad statement.