R. Yonah: They always think how to be careful in their deeds from theft and every sin and [monetary or verbal] affliction. The verse informs the Midah of Tzadikim, so you will adopt it.

Malbim: One who is Choshev does not yet have Etzah (counsel). He considers all possibilities - if to do, how to do. After he decides, he has Etzah. E.g. in war, he takes many Etzos to oppose the enemy's Etzah, for he does not know the enemy's Etzah. Tachbulah is a bind of many Etzos. Tzadikim's simple Machshavah is Mishpat. They go in the way of Mishpat and Tzedek, and do not veer from it. They do not need Tachbulos; Machshavah to do Mishpat, the straight path, suffices.

R. Yonah: Not only do they not have a heart to beware of afflicting - they think deeply how to swindle. Hashem gave Sechel to man to recognize Him and serve Him; Resha'im use it to do evil. They sin in deed and in intent, since they carried out their intent - "Hoy Choshevei Aven u'Fo'alei Ra Al Mishkevosam" (Michah 2:1). Also if they do not carry out their intent, they will be punished for it, like Chazal said ¹ . Tachbulos is thinking deeply about a matter, until he understands its end - "v'Navon Tachbulos Yikneh" (1:5). The verse teaches punishment of Resha'im who are Chachamim to do evil, and think that strategies and schemes. They could have used their Sechel in proper paths! Their desire drew them to scheme. The verse teaches to believe that Resha'im's end is destruction; their Nefesh will be utterly destroyed, for they anger Hashem with their bodies and Sechel.

Malbim: Resha'im need Tachbulos (collections of Etzos) to veer from Mishpat and trap people via schemes.