I don't think btilly is bike-shedding here. He's not arguing about whether you're right or wrong about labor unions. He's talking about whether or not your (new) first example actually supports your thesis (part of your thesis being that you have to choose between inoffensive writing and clear/concise writing).

You give two versions of the "labor union" paragraph. One of them does not say whether early union leaders were heroes or not (but might carelessly be read to imply that they aren't). The second states that they definitely were.

The second version is less offensive to people with pro-union biases. But it is more offensive to people with anti-union biases. If you wanted to avoid offending a particular person or group, your rewriting approach would work. But to avoid offending a diverse population you should instead remove any claims (express or implied) about unrelated controversial topics, or simply choose less divisive topics for your examples.

As mbrubeck said, I am not arguing about labor unions. I am arguing that your second paragraph does not offend labor union supporters because it says something different, and not because it says things at more length. Which contradicts your thesis that conciseness and politeness are at odds here.

To illustrate how different the two paragraphs are, the first paragraph could easily be a lead-in to an essay that argues that an environment that requires personal heroics from leaders drives away the dreck that are mismanaging labor unions today. This would be an example of the "sudden about face" that I referred to in my earlier response. The second paragraph could not be used to start that essay. Nor could the concise third version that I offered. The fact that one naturally leads to an argument that the other two do not proves their inequivalence.

That said, you're right that I was wrong to bluntly state that your first version said that labor unions weren't founded by heros. It says that anyone who claims that has difficult problem to explain, which leads people to conclude that they were not founded by heros. But doesn't state that conclusion. And, as I noted in my initial response, room has been left for solving the difficult problem instead.