He's referring to Teach's slaves in Hachinosu.
Anyway, If Imu is Elden Beast, then Teach is still the equivalent of Radagon, AKA a penultimate boss that might actually get folded alongside the final one in a fairly short time.
Teach did commit crimes though, it's just not as heinous as the noble's because he doesn't have the scope of their power yet.
- Attacked and likely pillaged Drum Island
- Pillaged a Banaro town then subsequently obliterated it
- Stole a Marine battleship and killed literally everyone onboard for good measure (as a Warlord)
- Started a free-for-all in ID level 6, in which they murder each other, allowing several nameless level 6 prisoners to escape for the outside world
- Threatened the world population on TV like a terrorist and casually sent a massive tsunami towards Sabaody Archipelago
- Approved of Necrophilia
- Approved of the canonically worst criminals alive as his henchmen
- Kidnapped a 15 year old girl
- Publicly owned slaves in Hachinosu