I think your opinion is pretty harsh tbh. Regarding emilyispro, Jagex (not Mat himself) issued the relevant ban for the offence then after that Mat simply defended her against a torrent of abuse from the sometimes toxic OSRS community.
Regarding RuneLite, he made the correct decision in the end but I think he was initially guided by higher forces in Jagex plus their legal team who were trying to persuade him to get rid of RuneLite.
Even if you consider these two issues as big errors I think the other stuff Mat has done for OSRS far outweighs this. It's very likely that OSRS would have died without Mat K and we wouldn't be sitting here discussing it.