Why does it say "v'Gam Hu Chacham"?
Radak: Also Hashem is a Chacham, and He knows their thoughts. They did not seek Hashem, and descended to Egypt for help, for they thought that Hashem will not help nor harm. Therefore Hashem brought evil on them, to teach that He does benefit and harm, and the help they thought to get from Egypt will not help.
Malbim: You think to seek strategies against Hashem's decree upon you. He is a greater Chacham, to carry out His decree in practice!
Which words were not removed?
Rashi: "V'Heshivecha Hashem Mitzrayim ba'Aniyos" (Devarim 28:68). This was Midah k'Neged Midah. I told you "Lo Sosif Od Lir'osa" (ibid.), and you went willingly. In the end, you will go to exile [there] Bal Korchacha (against your will)!
Radak: What the prophets said in His name. He fulfilled them, so people will know that Hashem oversees people's affairs and speaks with Nevi'im and sends them to rebuke people. When they see the evil that the Nevi'im spoke about in the name of Hashem, that it comes upon them, they will know that He sees them.
What is the meaning of "v'Kam Al Beis Mere'im"?
Rashi: This refers to the 10 tribes, who are Beis Mere'im, and Egypt, who helped them.
Radak: Beis Mere'im are Yisrael; "Po'alei Aven" are the Egyptians. Malbim - "va'Yave Ra" applies to Beis Mere'im - the evil Shevet Efrayim. You intend to nullify His words via calling to Egypt for help - "v'Es Davarav Lo Hesir" due to this. "V'Kam" applies also to "Po'alei Aven", the Egyptians, even though there was no decree against them, lest the decree against Efrayim not be fulfilled. The Egyptians wanted to nullify His words!