Well sure but are there evidences behind these accusations?
Yes, but it's ultimately circumstantial, so it's really down to interpretations of various examples of play behaviors which are suspect. They have fostered good will here, so therefore, if you don't want to believe their play behavior is suspect, you probably won't care. Could (and have) talked about it, but there's very little nuance to discussing this on WG. I'm just a big mean bully, clearly, even though I've played with hundreds of players and never done this with any of them.
Conversely, let's say someone is legitimately cheating, that standard of evidence probably will never be met. Like if I decided to cheat, tomorrow, you'd maybe have reasonable suspicions, but you will never ever catch me red handed (probably). So by understanding this, you'll understand that the bar is a bit different, for people who take the game seriously. Mafia is a game that cannot function with any form of OGI, it breaks the game.