What factors will act to limit the tendency of the workers' state to be captured by a new exploiting class (ie: as happened in Russia, China, etc) ? In particular, what would protect the right of "enemies of the state" (ie: either real enemies--or those falsely accused) to have access to the media? I think this is your question (please correct me if I am mistaken). In my view such "enemies" will have access to the media--regardless of how irritating or inconvenient this may be to government officials who are incompetent or hypocritical or corrupt.

Why will all political trends (including such "enemies") have access to the media?

Here is my argument: All future media channels break down into essentially two main categories:
(a) high labor-ratio channels with large audiences, and
(b) low labor ratio channels with smaller audiences.

What do I mean by "labor-ratio"? "Labor-ratio" is how many minutes of labor time are required to create a media product (ie: leaflet, newsletter article, email posting, web page, photo, song or movie) that consumes one minute of your attention time. For example a popular Austin Powers movie (we will certainly have better movies when the working class runs society--but in the meantime I will use this as an example) might require half a million human labor hours to create--but only require 90 minutes to watch. Hence the labor-ratio for such a movie would be more than 300,000. At the other end of the spectrum, my reply to you might require two and a half hours for me to write but only five minutes for you to read--yielding a labor ratio of 30. This would be ten thousand times lower than the Austin Powers movie.

a) low-ratio channels include things like leaflets, newsletters, email postings, simple web sites (and maybe some simple audio or web-cam type video productions). Everyone (including "counter-revolutionaries", etc) will be able to create such media because the principle of separation of speech and property will not give state officials the authority to interfere with your expression and distribution of your views when this expression and distribution is a result of your own labor. Ditto for the expression and distribution of media created by your political grouping or organization--because the labor involved is voluntary labor.

The principle of separation of speech and property only gives the state the authority to regulate (ie: censor) media productions that are the product of paid labor. This will serve to cripple the ability of those with wealth and privilege (some wealth and privilege will still be around for a while--because they will be necessary until the working class learns how to run the economy on an entirely new basis--without money and without all-powerful central planners) to amplify their voice with money (ie: as is normal under bourgeois rule--where the rich and their corporations dominate the mass media and saturate it with their propaganda and world view).

What factors will make certain that the principle of separation of speech and property is itself not abrogated (or gradually eroded away) by those corrupt officials in the workers' state who find that this principle crimps their style? The main factor here will be the political consciousness and political will of the overwhelming majority of the population -- which will recognize that the separation of speech and property is a principle worth fighting for.

b) high-ratio media channels (ie: things like movies or sophisticated media products) will also provide access to the views and agendas of all political trends in society. The mechanism here will be less direct than in the case of low-ratio media. The workers state will, to a large extent, influence or control high-ratio media. At the same time the workers' state will be compelled to provide accurate, comprehensive and all-sided information and analysis about all trends because this will be the demand of the overwhelming majority of the poopulation who will express their demands thru such means as elections (many parties and trends, for example, will compete for positions of influence over culture) and spirited mass actions that will win the attention and respect of millions.

Please let me know if this addresses your question.

Next: Part 2 of my reply to Irving: the experience of the October 1917 revolution