The strike was called as a response to a call to participate in a general strike called for the whole of Korea by the militant unions. If the pilots did not support them, they could expect little support from them in the future. Because of the law concerning industrial action in Korea, the pilot participation was illegal, and everyone concerned knew that going in. The leaders of the pilot union knew the risks they were taking but chose to go ahead anyway.
And what did they ask for? More money? No, they refused an offer from the company for a pay rise, prefering to get the agreement to get rid of the foreign pilots instead.
And why the hatred (not too strong a word) of the foreigners? Why has nobody asked them why they fear a small group of pilots from all over the world who are there only to assist and help Korean Air, and Korea? They do not take jobs from Korean pilots, but allow for the airline to grow and prosper. The FOs are being promoted as fast as possible (far quicker than they should, in my opinion) yet the airline is still short of captains, especially experienced captains. Yet you can give a Korean pilot nightmares if you whisper in his ear while he is sleeping in his First Class seat "foreign pilots!"
In response to pressures from the Korean Govt and US/Canada/UK CAAs, the company has taken much of the control away from the Korean pilots and tasked foreigners to run or advise on the running of Operations and training. They are running English language courses, and employing foreign pilots to boost the experience levels and give the Korean FOs a chance to see how it should be done. Of course changes are not being made fast enough, and many opportunities are being lost, but they should be given credit for trying.
Control of the airline is the real aim of the pilots. When they had it, there were more accidents and incidents, but that was an acceptable price to pay, in their opinion.
Losing that control was the real bone of contention, and the locals will do anything they can to get that control back. Anything.
If you guys really want to see Korean aviation join the 21st century you will support Korean Air, not the pilots.