Regrettably, a small number of people thought it was ok to set off fireworks facing other beach and park goers, rather than aimed out over the water, and some people even used them as purposeful weapons. While such conduct shouldn't result in punishing people who behave themselves, the situation each of the last two years was severely challenging for police and parks staff, I understand the choice.
You have never been allowed to set up random fires on the Beach.
This has also never been allowed, sure lots of people have been drinking, but its never been permitted.
While this seems a bit much, its also about irresponsible people who put their stuff on blast and annoy everyone around them, and even those living 3 blocks away.
Toronto can be overly restrictive at times; but in this particular case, I think it reads the same way as provincial parks banning alcohol at most campgrounds on Victoria Day weekend (but not the rest of the year); there's just been too much bad behavior and there are finite resources to control that. Sigh.