>>5336 (OP)
Because:
1) you agreed to do so in order to live on my land
2) you are surrounded by the monarch's loyal men
3) tea parties are awesome and you could be invited if your attitude improved
4) royal marriages come with NAPs and alliances, thus ensuring peace between the two nations.
5) you won't get taxed to death like you would in a democracy see France for the perfect example of being taxed to death
6) you and your family won't be replaced by dindus looking for free gibs
7) if the king makes tyrannical laws, than you know who to blame. Unlike a democracy where the blame is shared by the politicans and you.
8) you get the pleasure of joining the royal guard and all the benefits that come with it
9) you won't have to waste your time keeping up with the politics so you can "vote"
10) anime will become real
And much more