I think you're underestimating the degree of social intelligence required. To pull that off while still keeping the rationalistic habits that such people find offensive, you'd have to:

• Recognize the problem, which is nontrivial,
• Find a way of figuring out who falls on which side of the line, without tipping people off,
• Determine all of the rationalistic habits that are likely to offend people who are not trying to become more rational,
• Find non-offensive ways of achieving those goals, or find ways of avoiding those situations entirely,
• Find a way not to slip up in conversation and apply the habits anyway - again, nontrivial. Keeping this degree of focus in realtime is hard.

You'd also probably have to at least to some degree integrate the idea that it's 'okay' (not correct, just acceptable) to be irrational into your general thought process, to avoid unintentional signaling that you think poorly of them. If anything, irrational people are more likely to notice such subtle signals, since so much of their communication is based on them.