Whonix and Tails are OSes, meaning they could override what the browser tries to do in terms of network access. If Chromium prevents a plugin from directing all traffic to SOCKS, just take controls of Chromium's network settings from the underlying OS (Whonix, Tails).
Note: This just answers the question about browsers or other pieces of software that don't allow control of their network components. It doesn't address a vulnerability in that software.
Note: This just answers the question about browsers or other pieces of software that don't allow control of their network components. It doesn't address a vulnerability in that software.