Part 2 is correct in that trying to zero memory to "cover your tracks" is an indication that You're Doing It Wrong, but I disagree that this is a language issue.
Even if you hand-wrote some assembly, carefully managing where data is stored, wiping registers after use, you still end up information leakage.
"fast path"
The "right privilege level" allows you to see anything that happens during the execution of the lower privilege levels.