Extreme example: Team discussion about whether to buy A or B ends with decision to buy A.
Proponents of B are perpetually unhappy with the decision and will see any future crisis as an opportunity to push their agenda to get rid of A and buy B regardless of any correlation of crisis to A or B.
I don't want to be overly prescriptive in the question and eliminate good alternatives that I lack the imagination to think of. Might not be a single word, could be "cognitive bias".
A possible sentence might be: This person will assimilate all evidence into their "B" argument regardless of whether it fits, he's a "B" .