Earlier quoted context omitted.
Exactly. Blocking sites doesn't solve the issues, if anything it makes things worse. We need to be able to respectfully debate people we disagree with, not shut them out. This video pretty much outlines what I think about the recent US election and how I think we should look to move on from it: https://m.youtube.com/watch?v=GLG9g7BcjKs
There's no "debate" involved with these sites. They're webspam. When someone sends you cialis spam, do you reply with an email attempting to persuade them to stop sending unsolicited commercial email? Yours is yet another comment arguing from the faulty premise that "fakenews" describes sites like Breitbart. Breitbart is a horrible site, but it's not webspam fakenews.
No, that's not my argument. My argument is that what can start with filtering out spammy clickbait can easily evolve into filtering out sites that other people take seriously.
For example, Huffington Post is a news site that uses a lot of the same tactics as clickbait spammers, and tends to be fairly one sided in their worldview. To someone who disagrees with the worldview of the Huffington Post, why would they be less inclined to block it once the tools are in place?
In other words, once the tools are in place to block content everyone agrees is spammy, I can pretty much guarantee that those same tools will be used for semi-spammy content that some people treat as real news. This will almost certainly lead to increased political polarisation.
There's an alternative tool that works fairly well... if you see clickbait, remember that's what it is. We should aim to rise above low-information sites by providing better-thought-out counter-arguments.
As for your cialis example, if it was posted in a public forum like Facebook then responding to the article might not change the habits of those trying to sell you something, but it might make other people who read your comment think twice about signing up.