Compare the Psalm 1:1 note.
(1) The "simple," literally, "open," i. e. fatally open to evil;
(2) the "scorners," mocking at all good;
(3) lastly, the "fools" in the sense of being hardened, obstinate, perverse, hating the knowledge they have rejected.

Ye simple ones - פתים pethayim, ye who have been seduced and deceived. See on Proverbs 1:4 (note).

How long, ye (s) simple ones, will ye love simplicity? and the scorners delight in their scorning, and fools hate knowledge?
(s) Wisdom reproves three kinds of men, the foolish or simple who err out of ignorance, the mockers who cannot stand to be taught, and the fools who are drowned in worldly lusts and hate the knowledge of godliness.

How long, ye simple ones, will ye love simplicity?.... Simple foolish things, agreeably to their character, being weak simple men, men of weak capacities and shallow understandings; and such were the first persons that were called by Christ through the ministry of the word, even effectually; they were babes and sucklings in comparison of others, by whom they were despised as illiterate and ignorant of the law; see Matthew 11:25; though it may respect the Jews in general, who were externally called by Christ, and were a simple and foolish people, addicted to silly customs and usages, to the traditions of the elders, and loved the folly and darkness of them, and to continue in them, rather than the light of the Gospel, John 3:19;
and the scorners delight in their scorning; at Christ, because of the meanness of his parentage and education; at his disciples and followers, at his doctrines and miracles, sufferings and death;
and fools hate knowledge? the knowledge of Christ, and of God in Christ; the knowledge of the Gospel, and the truths of it; they hated the light of it, and did not care to come to it, but rather loved the darkness of the law, and even of error and infidelity; they hated Christ, the teacher of true and useful knowledge; they hated his person, though without a cause; they hated him in his offices, as a Prophet to instruct them, as a Priest to be the propitiation for them, and as a King to rule over them; such "fools" were they, and who are therefore expostulated with by Wisdom or Christ; which expostulations show their continuance in these things, and the danger they were in by them, the pity and compassion of Christ as man and a minister of the word, and the fervour and importunity of his ministrations.

simple ones--(Compare Proverbs 1:4).
simplicity--implying ignorance.
scorners-- (Psalm 1:1) --who despise, as well as reject, truth.
fools--Though a different word is used from that of Proverbs 1:7, yet it is of the same meaning.

The poet has now reached that part of his introduction where he makes use of the very words uttered by Wisdom:
How long, ye simple, will ye love simplicity,
And scorners delight in scorning,
And fools hate knowledge?
Three classes of men are here addressed: the פּתים, the simple, who, being accessible to seduction, are only too susceptible of evil; the לצים, mockers, i.e., free-thinkers (from לוּץ, Arab. luṣ, flectere, torquere, properly qui verbis obliquis utitur); and the כּסילים, fools, i.e., the mentally imbecile and stupid (from כּסל, Arab. kasal, to be thick, coarse, indolent). The address to these passes immediately over into a declaration regarding them; cf. the same enallage, Proverbs 1:27. עד־מתי has the accent Mahpach, on account of the Pasek following; vid., Torath Emeth, p. 26. Intentionally, Wisdom addresses only the פתים, to whom she expects to find soonest access. Between the futt., which express the continuing love and hatred, stands the perf. חמדוּ, which expresses that in which the mockers found pleasure, that which was the object of their love. להם is the so-called dat. ethicus, which reflexively refers to that which is said to be the will and pleasure of the subject; as we say, "I am fond of this and that." The form תּאהבוּ, Abulwald, Parchon, and Kimchi regard as Piel; but תּאהבוּ instead of תּאהבוּ would be a recompensatio of the virtual doubling, defacing the character of the Piel. Schultens regards it as a defectively written Pail (in Syr.), but it is not proved that this conjugation exists in Hebr.; much rather תּאהבוּ is the only possible Kal form with תּאהבוּן without the pause, regularly formed from תּאהבוּ (vid., Ewald, 193, a). The division by the accent Mercha-Mahpach of the two words תאהבו פתי is equal in value to the connecting of them by Makkeph; vid., Baer's Psalterium, p. x. In codd., and also in correct texts, תאהבו is written with the accent Galgal on the first syllable, as the servant of the Mercha-Mahpach. The Gaja is incorrectly here and there placed under the תּ.

Scoffers - That scoff at religion and contemn the word and faithful ministers of God.