Why do dispensationalists "throw out" parts of the Bible?

Awhile back someone asked me why dispensationalists "throw out" the portions of the Bible they don't like. This person told me that dispensationalist arbitrarily assign the books of Hebrews-Revelation to Daniel's 70th Week instead of applying them to the Body of Christ in the Dispensation of Grace. 

Here is a brief list of examples from 1 Peter showing why dispensationalists believe he is writing prophetically to believers of the Gospel of the Kingdom in Daniel's 70th Week.

1 Peter 1:1 Peter, an apostle of Jesus Christ, to the STRANGERS scattered throughout Pontus, Galatia, Cappadocia, Asia, and Bithynia,
[These are not Gentiles, else they would not be "strangers" of those places. They are Jews that have been scattered, cf James 1:1, Acts 8:1]

1 Peter 1:5-10 says that they are waiting for their salvation, waiting to receive the salvation of their souls, and that the prophets spoke of the grace that is going to be brought to them at the Second Coming. That is obviously referring to Israel (Rom. 11:26-27, Acts 3:19-25, etc). Members of the Body of Christ have already received the atonement and we are already saved. Also, the grace age was a "mystery kept secret since the world began" (Rom. 16:25, Eph. 3:1-9, Col. 1:24-28, etc.). It was not spoken of by the prophets.

1 Peter 1:18 "vain conversation received by tradition from your fathers" That would be JEWS.

1 Peter 1:20 "these last times" Daniel's 70th Week, the last days.

1 Peter 2:5-9 says that they are "royal priesthood" and a "holy NATION". That would be ISRAEL. We have no priests in the Body of Christ, but Israel will be a holy nation of priests in the Millennium (Exod 19:5-6, Isa. 61:6, Rev. 20:6).

1 Peter 2:10 is a quotation of Hosea 1:9-11 and it is ISRAEL after the Dispensation of Grace is over (Rom. 11:25-27).

1 Peter 2:12 "Having your conversation honest among the Gentiles" That would mean Peter is writing to JEWS.

1 Peter 2:25, 5:4 "For ye were as sheep going astray; but are now returned unto the Shepherd and Bishop of your souls." Sheep and Shepherd, that would mean Peter is writing to ISRAEL. (Jer. 23:3-4, Luke 12:32, Isa. 40:11, Matt. 4:35-36, 6:34, 10:5-7, 15:24, Ps. 77:15-20, 78:51-53, Jer. 31:7-10, Ezek. 34:1-31, etc)

1 Peter 3:20-21 Noah's flood and the ark is a type of their salvation. Which means Peter is referring to Israel in the context of Daniel's 70th Week (Isa. 54:9, Matt. 24:37-39)

1 Peter 4:7 "But the end of all things is at hand" Which means he is writing to those in Daniel's 70th Week (Matt. 24:3)

And there are many examples like that throughout Hebrews-Revelation, not to mention the fact that Matthew 19:28 and Galatians 2:1-9 plainly say that Peter is an apostle of Israel and not the Body of Christ. 

Contrary to the  anti-dispensationalists, right division is not an arbitrary doing away with certain portions of scripture. It is simply acknowledging what each book of the Bible says about itself and looking at WHO is writing and WHAT they are writing about. 

--Eli Caldwell