Using a 180 cast flat nose (or heavier), I'd have no problems or fears using a 357 lever gun for deer, hogs, bears, elk, moose. Until you've seen it in action, you don't know what the hell you are talking about, and you should likely abstain from offering an ignorant opinion. Of course, feel free to look like an idiot.
The OP was seeking comment and opinion and the comments didn't sound ignorant to me. The gist of the comments is that , yes the .357 rifle will work but it has range and power issues vs. a .30-06 class big game rifle. Most 150-165 grain .30-06 loads produce velocity at over 300 yards that the .357 magnum delivers at the muzzle. It seems that most hunters owning a more capable rifle would use it for big game. Some folks like to use as least effective a weapon as is legal, such as archery. More power to them, but when you seek opinion and get one that is different from yours it doesn't automatically mean the giver is ignorant or an idiot. Most big game hunters that might encounter a bear would use a rifle that produces considerably more energy than a .357 magnum. I wouldn't quit hunting if all I had was a .357 lever rifle and I really don't want to be shot with one, but it has a lot more limitations than the more commonly used big game calibers.
