I think the steering claim has been disproved by the analysis of the ship's rudder. It was too small and the Titanic was too large to allow for rapid course changes. There is a good reason for tugboats.

Also, icebergs are very large below the water. The part you see is not the part that will get you.

I think that at the officer's meeting they describe they could have put forward the idea that they might have changed course to avoid the impact but...

On site, and without complete information, we humans tend to underestimate the extent of an accident. Usually it takes an in depth investigation to uncover the actual events that led up to the accident.

I am sure that Mr. Lightoller really believed what he wrote down but that does not mean he can be relied on to dismiss all those years of investigations.