13% mentioned that error handling was the biggest challenge with using Go. This was not a multiple choice question, but you had to pick one answer. We don't know how many people would consider it challenging. (This is typically why you have a 1-10 scale per choice.)

This doesn't mean the rest of the 87% enjoy it. Honestly, I'd rather the next survey included a question "are you satisfied with the current error handling approach"

That survey specifically asked for the "biggest" challenge. One could make a compelling argument for the survey answer "learning how to write Go effectively" being an extremely bad option to put on a survey, because it at-least partially catch-alls every other answer. Its no wonder it got first place.