Not necessarily. Newspapers have been doing this for years, and (the quality ones at least) frequently show letters that disagree and point out errors.
If vice.com wanted to show only comments that agreed with them, they could do that already.
And most sites (cant speak for these ) mostly do it alreadyly. Try saying that eg:wage gap doesn' exist and link some articles by economists - 9 out of 10 times such comments get "moderated".
I personally doubt that 90% of dissenting comments are deleted by site owners purely because they are dissenting. Go to any article on the BBC, Economist, Daily Mail, Guardian, etc, and the majority of comments seem to disagree with the author.
Perhaps comments are being deleted for not being respectful, because they're considered spammy, or for some other reason.
That was my first thought. Same thing newspapers used to do when people could send in comments (letters) to the editor, and carefully selected for publication (I used to work at a paper so I saw the process and discussions numerous times).
