This does sound like a rookie mistake, and I'll bet there's a dev somewhere saying "Oh crap" a lot because of it.
It's also a hardware design problem. NASA's human missions have a weight budget that includes multiple redundant systems. I have no idea if this probe had three of everything, but missions that do are more likely to be successful.
More subtly, I'm curious if the sensor failed or maxed out. The kinds of forces that would max out the sensor might also max out the probe. So it's possible it was already doomed after they were encountered.