Others != Government
The claim that “others helped you build” and therefore you owe the government something is apparently due to the theory that “others” == the government. I've discussed this before:
Maybe this can be analyzed using Cantorian set theory. According to Cantor, “a set is a Many that can be thought of as a One.” The claim that “others” are the same as the government can be considered a claim that the government is the set of others. On the other hand, if each human being is a Proper Class, then the class of others is an Improper Class (as John Conway put it).
Shakespeare's plays are in the public domain but that doesn't mean public funding has anything to do with them. (I've made this point before.)
The theory that “the public” is identical with “the government” might be responsible for the copyright extension nonsense. You can think of copyright as a bargain between authors and the public negotiated by the government. That means copyright extension is a matter of the government giving away the public's rights, which should be a no-no. If the public were identical to the government, then the copyright extension is a matter of the government giving away its own property, which might be okay and should not be second-guessed by the courts.
Applying the above reasoning to corporations will be left as an exercise for the reader.