Ok, let me explain. The only example on your list between two countries where the sub was lost due to a combat-hit-like cause was Kursk. Others Soviet/Russian were due to other reasons, not related to the torpedo hit survivability, ie
- 1/7 lost due to scutling.
- 3/7 lost during towing.
- 1/7 lost due to flooding (but as I note below Charlie series did not have boyancy reserves).
- 1/7 due to flooding (after a fire, so not relevant to this specific scenario)
The US losses on the other hand were both due to their hull weakness, which may be viewed as relevant in this context.
Kursk had an internal detonation of a carrier-killer 650mm torpedo, which lead to flooding of 3 compartments. Soviet desighn standard (with exceptions that did not follow it) states that submarine must maintain positive boyancy with single compartment flooding, this is where boyancy reserves come from (the submarine desighns that did not follow that standard may have less boyancy reserves - Charlie series or more reserves - Typhoon class).
That desighn standard implies that if hit by a lightweight torpedo that would flood one compartment would allow a Soviet patern submarine (with exceptions) survive while would lead to a certain death of a USN patern submarine.
p.s. the reason why Charlie (Charlie-I and Charlie-II) series of SSGNs were not desighned with standard reserves (speed/dive depth or any number of other things viewed as standard in Soviet practice at the time) was due to the desire to build those submarines at an inland shipyard. Sierra series SSNs (Sierra-I, Sierra-II, Sierra-III) managed to get their standard reserves via extensive use of titanium and other displacement saving measures.