We never said that tests prove the absence of errors. I will say that tests reduce the number of errors, improve code quality, and help avoid regressions - i.e. re-introducing bugs that were previously fixed.
A blanket statement like "Testing is a wrong way" is incredibly negative and is not constructive. What is the alternative? No tests, as is done in many organizations? I don't think so.
Tests are one piece of a much bigger puzzle - they don't solve every problem, but you'll have a lot more problems if you don't bother to write tests.