The study you linked does have a lot of great background, and drew very reasonable logic based deductions, but those deductions are not yet validated. They are certainly correct, but there is no data out of those deductions yet. To say X will increase alcohol harms is great and correct, but if you need to balance policies, you need some reasonable data to balance X vs Y. i.e. what are the public health risks of alcohol in parks balanced to at risk people forced into more dangerous areas or harassed by police?

As for the family space part. From my experience here in Montréal, drinking in parks doesn't mean drinking everywhere in parks. Drinking (along with smoking, vaping, and cannabis usage) is not allowed in areas designed for children; and can be further restricted based on the intent use of a park or an area of a park. For example, with my two closest parks, one has a play structure, sand pit, and splash pad; there is no alcohol at all. The adjacent park has picnic tables and an artsy pergola; alcohol (and smoking and vaping) are allowed. This same division of parks (or sections of parks) is common.

While I understand your concern with alcohol in public spaces, I'm reasonably certain that there are shared private spaces, such as restaurants and sporting events, where alcohol consumption has not led to negative outcomes or concerns about the familyness of a space.

There may be a cultural difference in Montréal compared to Toronto that allows drinking in parks to not turn the city into a libertarian hellscape with pints in hand everywhere; but I don't think so.