As I understand it, the OpenPOWER Foundation is basically a way for users and providers of hardware and firmware around IBM's POWER CPUs to collaborate & share specifications, etc. It's not terribly different than various other industry consortia, such as the PCIe SIG, the RISC V Foundation, consortia around memory & flash standards, etc.
So, the real question is how much responsibility do these groups have for vetting their members? How strictly should their charters be drawn, in order to facilitate this? Should these groups really be concerning themselves with policing their members and enforcing some ethical/political standard, or just focusing on the technical problems they're intended to solve... and let governments worry about which firms should be shut out.
I'm pretty firmly in the camp of just having government do the policing. If the US government wants to use this as a point of leverage against the Chinese, then let them blacklist Semptian. They've shown they're well capable and willing to do such things.
There's a down-side to this sort of action that's also worth consideration. I mean, you won't prevent these sorts of companies from eventually getting the tech they need to build their products - only slow them down. But, if the US government builds a wall around US tech companies, what's at stake is potentially the entire principle of having open and unified standards. So, you could have Chinese computers that use their CPU architecture, their bus standards, their memory technologies, etc.
Now, imagine China sells a lot of its hardware into African, Asian, and South American countries, and all of a sudden, you could find that US and European tech companies are completely frozen out of those markets, because none of their tech is in any way compatible with the dominant computer systems in use by them. Worse yet, which way will the Koreans and Japanese go? Maybe try to play both sides?
So, in my opinion, the US should be very selective and judicious in restricting cooperation between tech companies. It's a weapon that gets weaker with each use, yet the likelihood of blowback only gets worse.
The article is really vague about the kind of information being shared, but it's really low-level stuff around motherboard standards, BIOS, etc. for POWER CPUs.
It's not like they're trading data collection and analysis techniques, AI technology, or anything like that. These types of organizations are usually populated by a bunch of electrical engineers focused on the nuts and bolts of computer systems, who have very little to do with what else is going on, in the mega-corps they work for.