a) No one knows how the fire started, both sides were throwing molotov cocktails, and the majority of the crowd attempted to help evacuate the building.
You can see in numerous youtube videos that while some of the crowd helped the people out, others happily continued to throw incendiaries into the windows. Majority my arse.
b) Ally yourself with an enemy nation who has just invaded and annexed part of the country, take over buildings by force, then kill some peaceful protesters. You really expect to get a kind response?
Imagine that Yanukovich had done the same to the maidan thugs, what the current national guard does to civilists in Donetsk. For all his faults he was a saint in comparison.
They simply hand over half the country to actual murderous criminals and fascists?
Actual murderous criminals and fascists already own the majority of the country. What difference would it make?