I don't think it's nefarious but it is sabotage. There's long been an implicit assumption that optimization should be more important than safety.

Yes, languages do lack good mechanisms to mark variables or sections as needing constant-time operation ... but compiler maintainers could have taken the view that that means all code should be compiled that way. Now instead we're marking data and section as "secret" so that they can be left unoptimized. But why not the other way around?

I understand how we get here; speed and size are trivial to measure and they each result in real-world cost savings. I don't think any maintainer could withstand this pressure. But it's still deliberate.