Rather than acknowledge a kasha and seek a terutz, you just conclude that chazal were acceptable when they give you the history but not acceptable when they say repeatedly that Torah protects us.
What is meant on a simple level is that Torah gives us a kiyum,an existence, which is a huge miracle, while among hostile nations. The fact that we haven’t been wiped out despite attempts by everyone in every generation is a bigger neis than krias yam suf, says rav yaakov emden.