I don’t use Gnome Terminal,
But took a brief look at what might be the way to modify its settings (optionally system-wide), and at least superficially could be very different than bash and zsh which could be the reason why chruby might have stopped short of supporting…
https://wiki.gnome.org/Apps/Terminal/FAQ
From the Gnome Terminal Wiki FAQ,
It describes various methods but all seem to be something similar to bashrc but potentially configurable globally (all users).
So,
configuring Gnome Terminal support <might> require one of the commands on this page instead of sourcing the profile to re-apply changes as described for bash and zsh.
Speculating dangerously and admittedly could be completely wrong,
TSU