No one's saying that critique is off-limits because the story is in its early stages. What we're saying is that you need to tone down the attitude.
Being harsh doesn't give you authority, and it doesn't make your points any more valid than the others. Wanting basic respect and open-mindedness in a critique isn't cowardice, it's a reasonable expectation when the goal is to help the story grow. Not every response you receive is an excuse.