I don't think anyone believes that there should never be a subway extension or subway line that goes to STC. However, due to past mistakes (SRT technology) and the current situation (exploding costs), it really requires a compromise to "fix" the transit going to STC. Whether it be LRT in the SRT corridor, LRT on McCowan, Subway on the SRT corridor, Subway under McCowan, or some other innovative solution, it all comes down to costs and ridership.
I understand John Tory's idea of "we need to get on and build something" and the people of Eastern Toronto feeling neglected when it comes to transit infrastructure, but such emotions and perceptions need to be backed up by facts and reason.
If the situation was different, where the cost of the One Stop Line 2 Subway Extension was not 3.35B or the city had extra funds to spend and the Relief Line was already built, then fine, build it. But right now, the facts are not in favour of it and should not be built in it's current form, especially because the Relief Line will be full on day one and the system will still be at critical capacity.