Can I answer What is the price of a printing press? given that I know what the price is, but I also know it is not an open content and adding price would pretty much reveal all there is to know about a printing press? Especially with all the details of what about printing press can get costly, it would require pretty much full "flavor" text as well.
The question shows no research effort and should be downvoted. Beyond that, it may be better to answer with 'the answer is on page 20 of the Adventurer's Armory' than the 250 gp specific price, but answering is definitely okay.
Beyond that, I think you're wrong that the specific content in question is not 'open content'-- the Adventurer's Armory in general is not, of course, but the printing press is listed here and this seems to make that release official.
Paizo isn’t selling the printing press’s description as a separate product; it is sold as a part of Adventurer’s Armory. US Fair Use doctrine recognizes educational purposes as potentially being acceptable copyright infringement, so long as the usage is not going to unduly affect the work from which it is taken. How much of that work is used, and how integral that part is to the whole, is a strong consideration for a usage to be legal. Other countries have similar provisions in their laws. Without actually going to court, no potential Fair Use rationale is guaranteed to be upheld, but (and I am not a lawyer) this particular usage seems to fall well within guidelines for acceptable use.
Moreover, since this site makes a good-faith effort to respect copyright law, punitive fines are exceedingly unlikely. Likewise, since the printing press is a minor part of Adventurer’s Armory, actual damages would be difficult for Paizo to prove. As such, even in the case of a court action against the site, the remedy would almost-certainly be to remove the usage from the site and that’s it—and since things would never get that far, as Paizo would, in the hypothetical scenario where they objected, start with a cease & desist that this site would promptly respect and take down the content ourselves.
This site does not police copyrights. Let me say that again, because it has come up a lot in the past few weeks: This site does not police copyrights. We make a good-faith effort to respect copyrights, but ultimately finding infringements of copyrights and doing something about them is the responsibility of the copyright holder. We do this primarily because content removed from answers via C&D makes for bad answers, in much the same way link rot does (and, in the case of linking to infringing websites, the two issues are actually the same). Secondarily, we do it out of respect for and in welcoming of authors and publishers. At no point, however, does “enforcement of any particular country’s copyright law” become a site policy.
So judge questions and answers that way: “is this likely to get us a C&D and cause a mess?” In this case, the answer is a stunning “No.” Not least because the printing press actually is open-game content, establishing that Paizo is not overly concerned about its copyrights to this content. (Though note that this site does not actually license anything under the Open Game License, which would require us to host a copy of that license with a fairly-massive boilerplate declaration of all the open-game content referenced herein, which doesn’t exist on this site and frankly can’t.) Basically, if someone is asking for so much information that they could skip buying the book altogether—in particular if they are asking for actual copies of the book including its artwork and other non-open content—then that would be a reason to close a question. Short of that, though, it really isn’t a problem.
And if you personally object, you can always just reference the publication in which the information can be found, forcing the user to have access to a copy in order to look it up.