i havent heard of em except from dota and didnt even know they were in csgo
Then you haven´t watched alot of CS:GO/CS2 in the past. They had alot of known players on their roster in the past (e.g s1ren, w0nderful, sdy and degster). They were a dark horse because of them rebuilding their roster and picking up up donk, zont1x and sh1ro. As a team they hadn´t played on a international stage before and had mixed results in the other tournaments they played online. (@saikko)
Not for IEM no, a couple months ago you could have called them dark horses but ever since BetBoom Dacha and even potentially before that people knew donk was cracked. Sh1ro was also already considered a good awper though he had a slump before his recent form. The rest of the team were all good/average players and zont1x definitely proved he is a great player too this event.
I don't think Spirit were considered the favorites to win compared to teams like Faze/Vitality, however a lot of people knew they had the potential to do great if they could handle the pressure. This tournament was more of a prove you weren't a one hit wonder situation than them being true dark horses imho