Perhaps because even without cheating, he carried his team to major finals of his first ever major as a Tier1 player (although choked at the end), got immensely impressive stats, went on to win tournaments, MVPs, etc. Akuma literally lost every single map in the last event (except 1 map against Nemiga), in the presence of audio/video recording, comms recording, screen-recording, anti-cheat, gotv delay, etc. Forget about crowds.
PS: The entire team didn't necessarily cheat, but a couple of players were really really suspicious. I fully agree with what Valde and Hampus said about the clips, and I'm 2.1K elo.