Is there a way to left-click links in gnome-terminal or am I out of luck?
There doesn't appear to be. If you really wanted that, then you would probably have to patch it as you said.
A helpful way of thinking about it is to open links sort of as a mouse gesture: Since Open Link is the first item on the right-click menu, a quick, small swipe to the bottom-right will open it with one click.
There's some activity on this on these bugs, however:
- https://bugs.launchpad.net/gnome-terminal/+bug/507109
- https://bugzilla.gnome.org/show_bug.cgi?id=540023