Different explanations on the analysis of the sentence

We maintain our position in order to defend the rights of the general public, mainly TV viewers, who are also product consumers.

I found the sentence in a textbook and there are different explanations on the analysis of the sentence.

1) the two commas are used for apposition and who modifies the general public as a pronoun of defining relative clause and who can be replaced to that.

2) the two commas are used for apposition and who modifies mainly TV viewers as a pronoun of defining relative clause and who can be replaced to that.

3) the comma in the latter is used for the one for non-defining relative clause like 'Tom, who can...' and who adds the information of the general public and who cannot be replaced to that.

4) the comma in the latter is used for the one for non-defining relative clause like 'Tom, who can...' and who adds the information of mainly TV viewers and who cannot be replaced to that.

Which analysis of them is correct or do you native English speakers have others?

What do you native English speakers think? Thank you so much as usual in advance.