Yes, they believed they'd shatter the TS Magnus, but collapse is completely different, so they're still picking it, and the team trusted him with that hero. That's one of LGD's mistakes; they should've respect ban on Magnus, and I think it's a bad decision to display their awesome draft (lycan tiny) in the battle between team secret; perhaps team spirit already knows about this draft and is preparing for it. I checked Team Spirit's recent matches, notably in the Easter qualifiers, and they've managed to stay in the upper bracket, indicating that they're more than just a normal dota2 team.
They did become confident that they can beat Collapse's Magnus again. If I were their coach, I'll respect it and will ban it for the entire series. Although there really are heroes that can counter Magnus but it's still going to be different from most of the games if there's a comfort hero that has been banned. As I've read xinQs post in weibo since there's an issue that's rotating towards their coach, he said that even they'll ban Magnus, Team Spirit, all of them, have a large hero pool.
Have a large hero pool is always having that kind of advantage because opposing team will really be having that fucking hard time on which hero should be banned its true that if they do banned out Magnus
but still wont really be a guarantee that they would win up but i do agree that they should have banned it if they do based up on how this Collapse magnus did really play well and make other teams go home
then as a coach then i wont really be doubting on banning this one directly but well its their choice and its too late to whine now.