Vinegar is a good disinfectant because it is acidic. It actually is a mild poison. In fact, it could even kill you, but you'd have to drink A LOT of it! (Probably a gallon or more all at once.) Don't worry...the amount of vinegar in your salad dressing will never hurt you. :) Like wine, it would take huge amounts of vinegar to hurt you and small amounts are harmless.
Why are there other bathroom detergents on the market? Well...2 reasons. 1. Sometimes you need abrasion, and vinegar is not abrasive. 2. Money. If someone can convince you that their disinfectant is the best, you'll buy it, even if vinegar would do the job for less money.
By the way...Windex does have its uses. I use it for everything BUT windows. (It always seems to leave streaks on windows.) Windex makes a great odor eliminator. It also makes mosquito bites itch a lot less. Vinegar doesn't seem to have much effect on mosquito bites. I also use Windex to kill any fly that gets into the house...superior to a fly swatter because you can stun the fly in mid-flight (then give him a good spraying once he lands)...plus you don't have the mess of a squished fly if you use Windex.
So what about streak-free windows? Surprisingly, the best solution isn't Windex or vinegar. Streaks are usually caused by a PH that is isn't neutral, and Vinegar is too acidic, while Windex is too base. The best solution? Plain old water and 2 Microfiber cloths. I use a wet Microfiber cloth to clean and a dry one to buff the window dry. I zip right through the job in no time and the windows sparkle.
You can buy microfiber cloths all over the Internet. Some sites:
http://home-solutions.hsn.com/dura-fiber…
http://amishfurnishings.com/webstore/pro…
http://www.bestofasseenontv.com/MicroFib…