I mean it really comes down to logics and common sense.
Why would people who spent years developing a huge mod for a game ruin it by distributing malware?
Why would people who have the skills to create such a mod write malware that is detected by av software?
Why would thousands of people, some of them also having reverse engineering/coding knowledge, play on pluto and not complain about any malware?
On the other hand:
Why would plutonium staff admit to you that they ship malware?