This type of attitude is creating a culture where everyone is "to scared to learn" by being to scared to comment on things, or even to ask a simple question.
So sad to see this...
However the OP's advice was basically "don't write tests because they slow you down." They even said that 100% code coverage was "a really bad idea". The OP's attitude was flippant, dangerous, and IMO, stupid. Don't follow this advice.
Having said that, to be more OT. I agree with you regards the code coverage. However, the quality of Tests should be raised, as i would rather be in a position where people are aware that stuff can break and be on their toes, then to have false sense of confidence with 100% code coverage using poorly written tests (for example, tests so complex they need testing on their own).
And sometimes, it is more important to get an MVP out there, and collect the users feedback then the actual tests.
My point, its a dynamic world, and it doesn't hurt to listen to each other more!