Soviet engineering wasn't sloppy. It was designed for robustness, loose tolerances and simplicity. It was well thought out design. In the same way that as much thought went into the cheap alarm clock than went into the Rolex watch, maybe even more so, the engineers just had different requirements.

It takes a lot of work to make cheap, low precision parts work together reliably. The Rolex has it easy, all the parts are precisely built at a great cost and everything fits perfectly. With the cheap alarm clock, you don't know what you will get, so you have to account for every possible defect, because you won't get anything better with your budget and the clock still needs to give you an idea about what time it is.

The parallel in software would be defensive programming, fault tolerance, etc... Ironically, that's common practices in critical software, and it is the most expensive kind of software to develop, the opposite of slop.