> Why do you care about "Milton's main message"? Is that more important than the historical results of his writing?
Because this review of Eade's interpretative book focusses on Eade's chapters that are the most significant to the reviewer writing for The New Statesman. It's quite a few steps from Milton's source text. I'm not claiming that Milton's message (and yes, there were several) is more or less important than how people have interpreted it, just that sometimes going to the primary source (rather than a review of an interpretative review) can be rewarding in its own right.
> Marx didn't intend to invent sociology, yet he did. What do you think about that?
Interesting question! Perhaps I'll go for a pint at one of the venues on the Karl Marx pub crawl [0] and see what the regulars think of it. That should be valid, shouldn't it?
[0] https://en.wikipedia.org/wiki/Karl_Marx_pub_crawl