Because Toronto is still a fairly immature North American city that fails to offer families the option of not driving everywhere.
A giant casino entertainment complex here would likely price families out of the area completely if it's a success - and turn the area into a very undesirable place to raise kids if it's a failure.
Regarding your first point, Toronto needs a DRL whether this particular redevelopment occurs or not, and only improving our city with better public transportation options will fix the "driving everywhere" issue. In regard to this proposal though I see nothing that will have anything much to do with the quality of life for families in the area. There are few now, and not likely to be many more of them in these few blocks whether this gets built or not.
In regard to what the area would be like if the casino failed, there is not a chance in hell that this project would fail if it were to be built as imaged.
If Toronto was a more mature urban area - where generations have grown up in high-density neighbourhoods and know how to behave in such - a casino wouldn't necessarily have these effects.
This area in particular is important because it's actually a really peaceful and friendly part of the city, quiet but not dead, and is walking distance to many diverse employment opportunities.
People learn far more quickly than you give them credit for. If you can think this through, others can too. Why would you think that only you and a select few others might know how to behave in such high density?
The characterization of this area a "peaceful and friendly, quiet but not dead" is bizarre to say the least. Sounds more like Gerrard and Woodbine to me.
I feel Cityplace is shaping up to become a fantastic neighbourhood in the next few decades, as the city is built out and more people make the city their 'home'. But if you put a casino here it'll continue to act as a bedroom community for those moving out of their parent's suburban homes and looking for action.
The way we treat families and seniors in North American downtowns is appalling and highly disruptive to the way a large sector of the population perceives the city.
I think CityPlace is turning out better than many do, although too much of it does look the same. If it fails though, it won't be because of this one project: the city is far too complex to dump it all at the feet of a casino and appendages. To reiterate my stand, it is proper transportation that is our biggest stumbling block right now, and the city needs a DRL whether or not this goes ahead. Failure to build a DRL will cause cascading failures in surrounding areas far more than building Oxford Place will.
The families and seniors comment, especially the seniors comment, sounds like sky-is-falling fear-mongering to me. Certain areas appeal to certain groups. You simply are never going to have every area appeal to everyone… so big deal. Make things accessible, great, but if you're saying that this area should remain "quiet", or something along those lines to appease certain portions of the population, I say you're asking too much. If every area catered to everybody, then everything would be the same. I don't want a monoculture city to live in. I want leafy suburbs in appropriate spots, and I want over-the-top pizazz the right spots too, and I'm not sure there's a better spot in town for what's being proposed here (as long as we get better public transport).