If you read it again you will notice that technically he thinks that, to satisfy those who believe the wealthy don't pay tax, Canada could use a system to encourage the wealthy to claim income, where that is incentivized by being able to vote. Often the wealthy have no need for income as they already have so much wealth and can easily borrow against that wealth as cash needs present themselves. It is believed (at least as far as the thread went) that the wealthy currently don't pay tax, and thus would be unable to vote, or their vote would count for little, under the proposed since they don't have sufficient income to qualify.
Why would they care? The ultra-wealthy impact election through donations, which is many order of magnitudes more impactful than their personal ballot, even if you were to give them 10x weight. Elon Musk impact on the U.S. election wasn't because he drove to the booth.
That would be true if he advocated for votes according to effective taxation rate or something similar. He caps his example at 800k reported income, if I remember, which is a rounding error to his income class.
Instead, he makes sure to include the idea of stripping low-income people of all voting rights.