I find it interesting that so many here are so quick to decry and dismiss any validity in the concept of a monarchy when I've never been convinced that democracy or whatever other governmental power structure one supports is any better. While the idea of a monarch being appointed and gaining authority via God or some other religious institution does not resonate with me, I do not see the very idea of someone being raised from birth to rule as inherently heinous in and of itself. In my opinion, those who seek power are rarely those who deserve it and those who are deserving will rarely seek it. All I need to do is take a cursory glance at any given selection of democratically elected leaders to confirm this position for myself. Will a lot of bad people end up on the throne? Absolutely, but not every person that wears a crown will abuse their power and intentionally bring suffering to their subjects. If my assertion on those who seek power is correct, then it honestly seems less likely to me that genuinely good-hearted leaders will be sworn in under democratic practices, but as democracies tend to have rather short terms the statistical probability that a few will get in from time to time does shoot up.
As for colonialism and imperialism, yeah, those are indefensible from a moral standpoint but I don't see how they're intrinsically tied to monarchies either. It will be hard to convince me that colonialism doesn't happen within modern democratic systems, especially when most modern democratic powers were built on colonial foundations. Individual wars under traditional monarchies may have been much more common but I feel that is simply due to technological advances allowing fewer seats of power to control much larger regions in the modern day, which reduces the total number of world leaders and thus statistically decreases the chances for conflict. However, thanks to that same technological advance the conflicts that do happen are on a much larger scale and have much higher stakes.