Neither does Judaism. And Christianity even to this day exalts kingship; the relationship of the king to God is stamped deep on European history. Paul and Jesus preach subordination to God and to the Church; they don't preach independence of thought or skeptical enquiry.
The imperial language of Judea was Greek (whatever Monty Python says) and Greek thought had influenced Jewish thought from the time Alexander conquered parts of the Levant and North Africa around 300 BCE.
Christianity began as a very small Jewish sect in, apparently, Jerusalem, (There's not a single contemporary record of it.) Its concern was the imminent coming of the Kingdom which the Son of Man (apparently Jesus, but not so specified) would establish on earth in the lifetime of Jesus' audience (Mark 9:1, Mark 13:28, Matthew 10:23, Matthew 16:28, Matthew 24:32, Luke 9:27), and the message was very simple: Get ready!
And, as Jesus said, pay your taxes meanwhile.
(John is different in this respect; by c. 100 CE when John was written, that idea is plainly, ahm, unhelpful, and is quietly dropped.)
I see nothing about democracy in early Christian thought ─ the instant Christianity began to grow, it had bishops to tell you what to do and think. I see kingship as a centerpiece fixture in Christian thought until the 17th century, and it's still close enough to touch even now.