Anon, chazal were fully aware of their own history – that’s how you know about the tragedies that you describe. And they say that Torah protects us.
You’re just spewing kefirah and it’s not helpful in a time of tzarah.
Torah protects in ways above our understanding. It also doesn’t prevent every decree – do you think the churban, Holocaust, crusades, etc…happened all of the sudden? There were warnings of calamities from.neviim and gedolim. People ignored them, and so they came; you might ignore them too because you’ll think “we’ve had suffering before even when I think we’re been behaving well”