Most of the marines he was talking to weren’t active during Roger’s era. Why would they care about that more than oden being part of the crew that the entire marine army fought just two years ago???
Also Sengoku immediately goes against your argument since as the highrst ranked marine during Roger’s era actually attributed oden as a Roger Pirate primarily.
Oden had been inactive for decades (we the reader knew him to be dead). It's not like Sakazuki was trying to rally them against him by calling to their feelings or something... That whole conversations focused on historical events and how they relate to the present. The marines were just given a full run through of the Rocks pirates for the first time ever, a crew they had never faced and never will face, since it was context to the Kaido/BM alliance.
Oden's very last journey as a pirate was his voyage with Roger. You would expect Sakazuki to bring that up if he knew about it or recognized his individual role as relevant considering that trip led to Raftel and the One Piece which are still crucial to the modern marines. That would have been a clear connection to current conflicts but he instead mentioned his role as a WB pirate and left it at that. This is pretty clear indication that his most relevant moments as a pirate, from the perspective of the marines and thus the world at large, is as a WB Pirate.
Sengoku only mentions him as a passing remark while leaving the room, a last bit of speculation since he is still pondering what was his relevance to all those individuals. He doesn't place his role in Roger's crew above WB's but clearly speaks of him as an enigmatic figure. None of that goes against the fact that his WB division commander role took primacy for Sakazuki someone who would have taken orders and reports on intel from Sengoku himself at the time.
Point being general statements on the strength of the Roger Pirates do not take Oden into account as his already obscure status as a pirate is primarily associated with the WB crew. It all makes sense considering he spent only 1 year with Roger and didn't take part in a single of the battles and rivalries that built up the reputation of that crew over their decades of activity.