While your argument about the importance of free speech is correct, you must notice the difference in power of a corporation and a government. When a government wishes so it can forbid you from voicing your opinion anywhere in the country, whereas a corporation can only forbid you on those media that it controls. There is little need to use a constitutional amendment to protect you from the evils of corporations, as you can easily use a service from another corporation yourself.
Whether or not they are allowed/forbidden by law to squelch your right of speech, the nature of corporations means they simply aren't able to.
Slashdot Mirror
How do you match braces? Do you actually count them? Or do you look at... the indentation of the closing brace?
While your argument about the importance of free speech is correct, you must notice the difference in power of a corporation and a government. When a government wishes so it can forbid you from voicing your opinion anywhere in the country, whereas a corporation can only forbid you on those media that it controls. There is little need to use a constitutional amendment to protect you from the evils of corporations, as you can easily use a service from another corporation yourself.
Whether or not they are allowed/forbidden by law to squelch your right of speech, the nature of corporations means they simply aren't able to.