Arrgh .... we've got two things going on here that are getting mixed up Suzann - canning fresh corn and freezing fresh corn. I guess maybe I confused you when I posted one answer to address a couple of your previous posts that talked about both canning tomatoes and freezing corn. I'm sorry if I did.
The tomatoes you put up are high acid - so they can be processed in a boiling-water bath.
Corn can be steamed or blanched and shocked (to stop the cooking) and then frozen without any problems. The reason for steaming or blanching is to kill the surface bacteria. The cold of the freezer will prevent the growth of bacterial spores. Of course, corn can be fully cooked before freezing, too.
Now - why you can't "can" low-acid vegetables without a pressure canner. Here is the explanation that you would have found if you had read the link in my previous post to amber:
"The spoilage organism, Clostridium botulinum can be present in any food. It is itself destroyed at boiling temperatures, but it has the ability to form toxin-producing spores that can survive the boiling treatment. These spores thrive in a moist, low-acid environment without the presence of air – the exact conditions found in a sealed jar of low-acid food.
The growth of Clostridium botulinum spores is prevented when filled jars of low-acid foods are “processed” at a temperature of 240°F for the established time. The only way for a home canner to achieve a 240°F temperature is in a steam-pressure canner. (Boiling water canners heat only to 212°F, the temperature of boiling water.) Because Clostridium botulinum spores do not grow in the presence of acid, high-acid foods can be safely processed in a boiling-water canner."
I hope this helps to untangle where the thread got twisted between two different forms of preservation.