Your article is interesting, and a lot of the points you make are valid. In practice, LW-style rationality might well have some of the effects you describe, especially in the hands of those who use it or understand it in a limited way. However, I don't think your point is valid as a general argument. For example:

If you win too much, deprive those close to you the chance of winning, effectively causing them anxiety.

To me, this seems to be based on a fallacious understanding of LW-style "winning." Winning here means accomplishing your goals, and using a "rationality" toolkit to win means that you accomplish more of your goals, or accomplish them better, than you would have without those tools.

For some people, being right about everything is a goal. For some people, harmonious social relationships are a goal. For a lot of people, these are both goals, although they may be prioritized differently, i.e. a different weight may be placed on each. If the goal of being right conflicts with the goal of harmonious relationships, and harmonious relationships are prioritary, then according to the toolkit of "rationality", it is rational to lay off a bit and avoid threatening the self-image of your friends and family. This is certainly true for me. Being right, coming across as exceptionally smart, etc, are rather low-priority goals for me compared to making and keeping friends. (The fact that the former has always been easier than the latter may be a factor).

Naive use of a rationality toolkit, by people who don't know their own desires, may in fact result in the kind of interpersonal conflict you describe, or in barreling too fast towards the wrong goal. That would be improper use of the tool...and if you cared to ask, the tool would be able to tell you that the use was improper-and aiming for the wrong goal is something that LW specifically warns against.

Nitpick: there's something funny up with the formatting of this article. The text is appearing smaller than usual, making it somewhat hard to read. Maybe go back to 'edit' and see if you can play around with the font size?