I get the distaste for what can easily be seen as political opportunism. I think it's entirely possible that you are right that WSJ would not care about viewpoint diversity unless that position was benefiting them at the moment.
But after years of following endless cultural trench warfare carried out on social media, I strongly believe that focusing the debate on the perceived evil of certain people/organizations (like WSJ) doesn't help. I think it's actively toxic and prevents us from finding common ground.
I have no particular love for WSJ, but viewpoint diversity is something I feel very passionate about. This cause is being spearheaded by Heterodox Academy, who focus specifically on academia: https://heterodoxacademy.org/problems/
So even though I might disagree with WSJ on all sorts of other things, I'm still happy to see them popularize an argument that I care about. I can feel "in coalition" with them on this issue, even if I might disagree strongly with them on other things. Pointing out contradictions in their argument (as you have done above) is totally fair game and could force them to reconcile these inconsistencies if enough people call them on it.
> I'm not here to argue the for or against the government intervention trying to prevent a narrowing of the diversity of opinion. I'm saying the WSJ does not give a crap about diversity. They have no real ideals. They only care when their side has a disadvantage.
I feel exactly the opposite: I'm not here to argue whether WSJ is a sinner or a saint. To me it's a fruitless question because even if you could prove they have bad motives, that doesn't tell us what we should think about this argument. People can make good arguments for the wrong reasons. That doesn't mean we should throw the argument out based on who is making it.
By the way, I say this as someone who has broken this rule countless times over the years. I don't say all this because I think I am better at productive argumentation than other people. I say this because I've spent too much time over the years on toxic discourse that goes nowhere.