Sodje's brother Akpo, introduced from the bench at half-time, fired home from 25 yards in the 56th minute to claim a point for the promotion-chasing Addicks in a game played in driving wind and rain throughout.
However, Skiverton said: "It's the second time in two matches that the Mason-Obika combination has resulted in a visiting defender being sent off. There was no doubt about it, Ryan was clean through."
Skiverton also lauded the performance of Glovers goalkeeper Alex McCarthy, who rescued a point for is side in the face of Charlton's second half onslaught, and the all-round workrate displayed by his side.
"Alex made five or six top-class saves," he said. "But overall it was an excellent team performance. In the first half we were very good technically and the second half was a story of dogged determination."