Ofcourse he can do what he likes, but the only real reason I see is your point number 2 - the rest is just mumbojumbo as I see it.
I mean...
Point 1: if he knows who it is, why not sue the guy? Should be an easy win, right?
Point 3: there is really no difference between "deisgned for book" and "designed for PDF". It would be like saying "This music is designed for vinyl - not for CD". Claiming that there is much of a difference, in my view, is a kind of useless elitism, really. Oh, and I actually prefer PDFs that I can read on my tablet opposed to more dead trees filling up my shelves. PDFs are also searchable, which I like, and I can read them on whatever device _I_ like, be it my phone, tablet laptop or whatever. It works for other books, so why not this one?
Point 4: Not releasing the book doesnt show solidarity with anyone. If he want to show solidarity, he should sue the guy.
Personally I dont care one way or the other, I have the old book here somewhere (at least I used to have it) and would not buy the new one anyhow, unless ofcourse there was some online edition I could easily pay for and download. I really dont need more books, got too many already. :-)
