These are the first lines of the cry of Wisdom addressing those "in the open squares," "in the chief concourses," and "at the openings of the gates in the city," meaning mankind in general. We can read into her words a touch of incredulity or even of despair, as if she cannot believe how dull and thick-headed people are for failing to grasp that their behavior is frankly stupid, foolish, and self-destructive.
Wisdom calls these people "simple ones," and the Hebrew word, peti, suggests foolishness, naivete, and a lack of sound judgment. As the Dictionary of Biblical Languages with Semantic Domains: Hebrew (Old Testament) explains, this word "pertain[s] to persons that are easily deceived or persuaded, showing lack of wisdom and understanding, yet having some capacity to change this condition." She, then, is speaking to ordinary people—mentally sound individuals—who have allowed themselves to be convinced, contrary to the evidence, that their lifestyles are good and profitable. "Scorners" and "fools," though technically different groups, are included in the whole mass of "simple ones."
Put even more simply, Wisdom is telling these people that they cannot fall back on the claim of ignorance as an excuse because they should know better! If nothing else, they should be able to see that the results of the way they live are harmful, ending in misery and death. On the other hand, God's way of abundant life and blessing is readily available and accessible in His Word, in natural law, and in the lives of those who follow His instruction.
So the obvious question must be, "If the right way to live is so abundantly clear, why do they not change?" Wisdom answers this in the last half of the verse: "For scorners delight in their scorning, and fools hate knowledge." In other words, their foolishness is deliberate; in fact, there is a kind of perverse stubbornness and rebellion in their refusal to change. They enjoy mocking and criticizing God, His ways, and His people, and they utterly despise truth. The apostle Paul summarizes this attitude in Romans 8:7, writing, "Because the carnal mind is enmity against God; for it is not subject to the law of God, nor indeed can be."
Solomon, then, is addressing unconverted humanity under the sway of "the prince of the power of the air" (Ephesians 2:2), who has defiled their natures with sin and rebellion and hatred of God. The godly way of living, as revealed in God's Word, is readily available, but the vast majority of mankind rejects it because they have allowed themselves to become convinced that their own way is better—not because the facts are on their side but because they simply do not want to submit.
This is why conversion is a matter of changing the heart, not overcoming ignorance. God must step in personally and by grace soften the heart of stone (Ezekiel 36:26) to accept His way of life.