Delight is not seemly for a fool - תענוג taanug, splendid or luxurious living, rank, equipage, etc. These sit ill on a fool, though he be by birth a lord.
For a servant to have rule over princes - I pity the king who delivers himself into the hands of his own ministers. Such a one loses his character, and cannnot be respected by his subjects, or rather their subjects. But it is still worse when a person of mean extraction is raised to the throne, or to any place of power; he is generally cruel and tyrannical.
“Delight,” high unrestrained enjoyment, is to the “fool” who lacks wisdom but a temptation and a snare. The second clause carries the thought on to what the despotism of Eastern monarchies often presented, the objectionable rule of some favored slave, it might be, of alien birth, over the princes and nobles of the land.