first of all, time savings will be in the tune of 40 minutes, if not more. Hardly "negligible savings". Second of all, you forget issues with the existing VIA corridor through Brantford. Curvy and full of freight traffic.
Then your "nobody goes to Pearson" claim. Today there were 8 flights from London international making the short hop to Pearson. Countless more made the drive down the 401.
Then you get to the point where the Brantford route doesn't even stop in Hamilton.
And also the fact that demographics of Kitchener are much more Transit friendly than Hamilton. Hamilton is an industrial economy, while Kitchener Waterloo has headquarters of companies with satellite offices downtown and a ton of business flight use.
You are also missing half the point of this proposal, which is not to serve London, but Kitchener and its Tech industry. Hamilton's economy doesn't need an HSR link to the airport, to downtown. A half decent speed regional rail service, sure. This HSR isn't aimed at London, its aimed at Kitchener with an extension to London because its cheap and makes sense.
The convo at MTO likely went like this:
MTO planner 1 - Hey, lets build all day 2 way GO service to Kitchener, we need to promote connections to kitchener, the airport, and downtown to build the GTHA as a venture capital and tech hub, as well as adress congestion issues on the 401.
MTO planner 2 - We should extend it to London as well, the feds are completely disinterested in doing anything with VIA and they could really use some better rail service.
MTO planner 3 - hey, look at this feasibility report I just whipped up. it says that Kitchener and London would be way better served with HSR than just GO trains running at 90mph..
Running it to London via Aldershot serves only London, and a bunch of suburban communities which would be better served by regional rail anyway. (Note, no Hamilton connection. the Aldershot route connects in Burlington, and it would be way too large of a detour to serve Hamilton) Running it via Kitchener serves Kitchener, a city not well served by regional rail due to overly long travel times to union, (roughly 30 minutes more than it would be for Hamilton), as well as Pearson airport. Whats more, travel times would likely be lower as well as construction costs, as costly realignments wouldn't be needed and track purchasing would be way cheaper. There is also the issue of heavy freight use on the Aldershot corridor, something that isn't an issue on the Kitchener corridor. Kitchener could probably build 2 tracks between Kitchener and London, while you would likely need 4 on the Aldershot alignment, jacking up grade separation costs.
Choosing the Kitchener alignment is common sense, I don't know why you are protesting it so much.