More testing is better than less testing

the choice is not "do test driven development" vs "you obviously don't care about quality in the slightest". Taking this attitude is just insulting the people you are asking to do more work.

maintaining the tests has overhead as well, it's not free. If they fail is it because the system is broken? or because the test didn't get changed to match the new way the kernel works? (and is the new way the kernel works actually going to work in the real world)