But remember, the section you are quoting is the perception that the other nations have -- it isn't an official pronouncement of divine ruling, but the other nations, realizing that they sinned and deserved punishment, and yet it was Israel that suffered, see Israel as getting punished when they, themselves should have been. As the Ibn Ezra writes, "In consequence of the troubles of Israel, the other nations had peace; the punishment which the latter deserved was inflicted upon the former."
There is the Noachide covenant which they are bound by which forbids violence, and requires that all acknowledge God and the rectitude of the Torah - in which case, oppressing the nation which God has established a covenant with would be a problem.
Israel becomes great for, among other reasons, its faith and its good deeds. There is a concept of reward, so as Israel has allowed itself to be the whipping boy for the world, and it has "bore the guilt of the many And made intercession for sinners" God assures additional reward. Also, from the Ibn Ezra "He prayed to God for the transgressors. Comp. Jer. 29:7"
The suffering servant is innocent and sinless-that's not true of Israel. The suffering servant was humble and voluntarily submits. Israel never voluntarily submitted to suffering. Israel never suffered for other peoples sins.