90% of my projects are failures, and the 10% which are successes would have never happened if I was too afraid to start them. The successes looked just as likely to be failures as the actual failures from the outset.

I disagree that "failure is bad and should be avoided". The degree to which failure is bad and should be avoided depends entirely on the gravity of the consequences. When taking on an ambitious programming project, "failure" is just an unfinished project and a loss of time. It's clearly a different world than something like quitting your job to try to become a professional actor.

Judgement shouldn't be based on whether somebody is failing at something or how many mistakes they are making, but the comparison of the positive vs the negative consequences. When learning something new, you will always make many more mistakes.

The problem with both the pithy quotes and your response (which is, I think, largely reasonable) is that neither one actually defines any criteria for success or failure, or what is an "unreasonable" number of mistakes. It just ends up being a semantic disagreement over what they meant by "failure" and what you understand by "failure", and I think you'd probably end up largely agreeing in the end if you broke down and actually explicitly defined the meanings of the words used.