Why shouldn't someone put sulfuric acid drain cleaner down a garbage disposal side?

I can not advise against using sulfuric acid, or any acid, in a enclosed area such as a rest room strongly enough. As a young boy I would take limed up toilet bowls out in the alley behind the shop and boil the lime out of them. Over half a century later my lungs still carry the scar tissue that the acid fumes caused. A few years ago I lost a good friend when he used a commercial drain cleaner containing sulfuric acid in a unvented bathroom. Acid IS NOT A GOOD IDEA to use to clear mineral buildup. Take it from one who's paid the price. Regards, Tom