Some people really hate connectivity. Instead of letting the riders using the eastern EE LRT and the northern subway transfer at Brimley, they'd rather send the riders all the way to Kennedy and then expect them to backtrack.
The "average for non-terminus stations" is meaningless. Obviously, a station like Steeles with its massive bus terminal will cost more than a basic station with pedestrian access only. And yet, Steeles is a non-terminus station (the subway does not terminate there), which meaninglessly pushes up the average.
Even if the Brimley station does cost $100 million, it is certainly worth spending that amount to improve the transit access and connectivity.
It ironic that some people want to squeeze in a station at Willowdale, where the gap between the existing stations is only 2 km, and any TOD would face an uphill battle with the local nimbys. And yet, other people want to preclude the SSE station at Brimley, leaving a gap of 4 km between the stations (assuming Lawrence East is built) and forfeighting TOD in the location where it would face no local objections.