Do not pray for this people God told Jeremiah - WHY?

Jeremiah Chapter 7: 14 Therefore will I do unto [this] house, which is called by my name, wherein ye trust, and unto the place which I gave to you and to your fathers, as I have done to Shiloh.
15 And I will cast you out of my sight, as I have cast out all your brethren, [even] the whole seed of Ephraim.
16 Therefore pray not thou for this people, neither lift up cry nor prayer for them, neither make intercession to me: for I will not hear thee.
17 Seest thou not what they do in the cities of Judah and in the streets of Jerusalem?

Jeremiah Chapter 11: 12 Then shall the cities of Judah and inhabitants of Jerusalem go, and cry unto the gods unto whom they offer incense: but they shall not save them at all in the time of their trouble.
13 For [according to] the number of thy cities were thy gods, O Judah; and [according to] the number of the streets of Jerusalem have ye set up altars to [that] shameful thing, [even] altars to burn incense unto Baal.
14 Therefore pray not thou for this people, neither lift up a cry or prayer for them: for I will not hear [them] in the time that they cry unto me for their trouble.

Jeremiah Chapter 14: 9 Why shouldest thou be as a man astonied, as a mighty man [that] cannot save? yet thou, O LORD, [art] in the midst of us, and we are called by thy name; leave us not.
10 Thus saith the LORD unto this people, Thus have they loved to wander, they have not refrained their feet, therefore the LORD doth not accept them; he will now remember their iniquity, and visit their sins.
11 Then said the LORD unto me, Pray not for this people for [their] good.
12 When they fast, I will not hear their cry; and when they offer burnt offering and an oblation, I will not accept them: but I will consume them by the sword, and by the famine, and by the pestilence.