Do you hold for this claim to be false?
It is a multi-part claim. I know this wasn't addressed to me. However, if we are following a universal form, the logic should be the same.
The insight we can derive from MBTI so far is that emotions suffocate dispassionate reasoning.
First, the use of the word "suffocate" either adds no content or makes the statement false if interpreted literally. Emotions do not "suffocate" nor is it possible for dispassionate reasoning to get "suffocated." Therefore giving critical thinking requires interpreting it as an analogy, but I believe it do be redundant.
Second, how is that the type indicator teaches us this? It is simply a test, that by design, places T and F on scale to decide preference. However, as is mentioned often in the literature, scoring an F does not indicate lack of logic. Again, the part about MBTI giving us a particular insight is highly suspect. It also seems irrelevant to the central claim you were making. If MBTI does not give us the insight in question, your statement is false. Therefore, I will remove that part also, and analyze what is left.
If we were to replace it with the statement, "Emotions are incompatible with dispationate reasoning." The statement may appear to be true for the simple reason that being "dispasionate" is incompatible with emotion. However, I submit a paradigm where "calm" is an emotion. It is a state of chemical activity, as are anger, anxiousness, depression, and others. Emotions are simply reflect our internal chemical states.
So at this point, I have interpreted your statement as, "Strong emotions are incompatible with a state of calm."
In order to think clearly, we must follow the logical form carefully.
I interpret thinking clearly to mean thinking accurately. Even if we follow logical form carelessly, we can still be accurate (simply because of prior practice and luck for examples). So once again, to give you the benefit of the doubt, I interpret your statement to mean, "Taking care in our reasoning aids in our accuracy of our reasoning."
If we are not dispassionate enough, we will stray from the logical form in favor of embracing chains of reasoning, premises and conclusions favorable to our personal values?
This part takes the most interpretation. Generally speaking, the choice of premises is the most difficult part of reasoning. Care must be taken to chose a set of premises that are "obvious." This is often a difficult task.
Nevertheless, loosing composure does not necessrily lead to poor reasoning. One reason, is that many people are so well practiced in situations so that they will reason accurately even when their sympathetic nervous system is at full arrousal.
But if I interpret your statement as "Stress is less conducive to accurate reasoning." I would agree with it. However, I have weakened your initial statement a lot to get to that agreement. Since you are making the claim, the burden of proof is on you to prove the initial stronger claim.