I have made an observation on the psychology of people who are strongly pro-civil rights, pro-peace, pro-cultural diversity and the like.
They may put a lot of effort into their favourite topic, but after years of such effort when faced by a similar topic but different taste of it, they may snap and turn with a convertite's fervor around.
The German greens provided anecdotal evidence for this: Their top politicians ranted for a decade against militarised foreign policy, arms exports and so on - only to become the top supporters of the ISAF mission.
Some people who looked like 150% pacifists have recently turned into IS haters wishing for military action against the IS.
A lot of "small government" ideology folks reliably turn into "big budget" folks whenever the topic is the "defense" budget.
Some civil rights movement leaders have had similar moments; still fighting for the interests of their own group against a favourite opposition group, they're often all-too easily lured into trying to oppress a third group.
It looks as if somehow the rational part of the brain got its way on the main topic, but after years the irrational, part finally got its way in a fresh topic. As if some kind of pressure was building up, only to be released by some kind of unexpected provocation.
I lack the researched rive and contacts to look up whether psychological research has discovered, confirmed and labelled this already. It would be interesting to know, but experimental confirmation would be very difficult.
The phenomenon - if existing - would be a major problem in the pursuit of rational, wise policies that face irrational, intuitive competing policy alternatives.