Because people want it that way; and they're going to get it that way; and all the effort wasted on changing it will mean more people homeless or poorly housed.
These rules are not unique to Toronto, nor are people here the only humans who have these types of preferences.
This is a forum as friendly to your cause as you will ever find. People here are broadly pro-development, pro-density, acutely aware of the housing crisis, and very open to and actively supportive of
government programs (ie Housing Now, Long Term Care, Student Housing, Rapid Housing etc.).
Yet, we broadly (not universally) like trees, sunlight, a modicum of privacy and see that housing not only needs to exist, it needs to be humane; a place people want to live, not just an alternative to the streets.
If you get push-back here, an idea is going nowhere fast in the broader community.
Lets get working on things that can gain support and happen, rather than induce blowback and opposition.
The goal is getting people housed, in good housing, in developments that serve the new residents well, and the communities they inhabit well.