Programming

I think what you are saying is technically correct, but it fails to acknowledge the importance of human emotions. Emotions are involved in everything humans do, and since software is written by humans for now, the act of developing software also involves emotions.

This does not mean that it should be a emotion-driven discipline or that emotional arguments should be weighted more than other kind of arguments. It just means that everyone will deal with human emotions while developing software, both their own and others'. We can of course manage our own emotions as we wish, but then the question is how do we act on regard of others'.

My main thought here is that disregarding how others feel about your actions rarely helps anyone. When collaborating with others, we usually aim for getting the most out of that collaboration. That is only achievable if the other person feels safe and welcome. Maybe writing some harsh comments in a code review is not the best way to do that.

Next thing that needs consideration is that we are all different, and what for one is a small gesture, for other might be offensive. You don't know everyone else's personal history, background or experiences, so you don't know what can negatively affect them. This needs to be acknowledged, particularly when working in heterogeneous groups (ie, people from other cultures). You can ignore this fact, but it will negatively affect the collaboration.

As with everything else, people can become better at communication and collaborating with others, and still be able to defend your points without being aggresive.

Why don't they, then? My first guess would be that this is seen as irrelevant. This is how I do things, how we do things in this industry, learn to deal with it. I don't think that is a good approach. It does not harm your engineering skills nor the product of your work to be kind to others. On the opposite, it makes their lifes easier. I don't see a reason why we shouldn't strive to do that.