More hours does not equal higher productivity. Working for six hours on a single commit (as the poster indicates) means the commit is far, far too large. Unless he means 'feature', then it's okay.

I don't see how you can make that deduction. You must be some kind of commit-nazi. Working hours do not correlate with the size of the commit. There might have been a number of hours just thinking about the implementation, designing the solution, fix, whatever, before writing a single line. The actual commit can then be e.g. 10 lines of code. There are many, many reasons why a single commit can take several hours of work. And it's perfectly fine and normal. Don't be judgmental like that.