1)
Why did they say "vi'Hyu la'Anashim"?
1.
Malbim: Let us be like people, who can sometimes defeat Bnei Elim, e.g. "Sarisa Im Elokim v'Im Anashim va'Tuchal" (Bereishis 32:28); animals can never do so.
2)
Why did they add "Pen Ta'avdu
1.
Malbim: [Even if they will defeat us, let us not be defeated so thoroughly,] lest they subjugate us. [And even if they will subjugate us, at least] let us fight [and not be like animals that are overpowered without a fight].
