Funny thing, the previous person with minimal earlier site presence who came in with "here's how to start properly growing Less Wrong" was also kind of tone-deaf and annoying.

If i wanted to insult him, I would do that much simpler.

Insults don't work that way. And I don't think you seriously believe that just because someone's insult could be simpler, it isn't an insult.

Besides, just because the explanation for an insult isn't simple doesn't mean the insult isn't simple.

I wanted to make an end to any idea of aggressiveness.

The only way you can end aggressiveness is by not being aggressive. You can't be aggressive and then add something at the end to make up for it.

Besides, it's not even a lie... I do feel some kind of brother or sister love towards everyone.

It has a meaning based on context, and the meaning based on context is not "I love all human beings". This ought to go in "geek social fallacies" if it isn't already; "it's literally true" is not an excuse. Words have connotations and implications, and it is your responsibility to understand them.

my rigorous attitude towards his arguments

You suggested that I likely haven't spend 5 minutes thinking about the subject which shows complete ignorance. That might be a honest belief but it certainly not rigorous.

Everybody regular of LW has thought about how to improve LW for more than 5 minutes. In my case I have even written tons of posts about the subject.

There are two ways to read this.
(1) You felt personally attacked and wanted to retaliate.
(2) You lack basic understanding.

It's very hard to read what you wrote and not come to the conclusion that (1) played at least a part.

I wanted to show open palms or something, but I cannot do that on keyboard.

And you failed. You communicated in a way that doesn't signal what you want to signal.