The Rouge River is red, so far as rivers go. French explorers renamed the Rouge in the late 1700s, inspired by the way the river's red clay banks melt into the water as it flows past. Before then, the Rouge was known as "Katabokokonk", an Iroquois word meaning "river of easy entrance."
Unless you live near the Toronto-Mississauga border, it is unlikely that you have been to Marie Curtis Park. It is at the very end of the Queen streetcar line at the bottom of a residential street in the Long Branch area.
The last reason - nudity - is optional. You don't have to take your clothes off to have a good time. You can remain covered, stick to the "clothing mandatory" end of the beach, and enjoy the dunes and the cityscape in their own right.
That said, Hanlan's Point Beach is most famous for being one of Canada's only two official nude beaches. (Wreck Beach in Vancouver is the other.) Skinny-dipping is the main attraction.
Opened in 2007, Gibraltar Point is the newest beach on Toronto's roster. Because it's new, or because it's not labelled on the tourist maps of the Toronto Islands, or because it is at the furthest point from any ferry terminal, Gibraltar Beach remains virtually empty on days when Centre and Hanlan's Point beaches are packed with people.
Technically, "Ward's Island" does not exist. You can take the ferry to the Ward's Island ferry dock. You can walk there from Centreville Amusement Park. You can see it from Cherry Beach or Leslie Spit. But there is no such place as Ward's Island.