They let an obscure Chinese OEM buy out IBM's PC division (now Lenovo). They let Toshiba buy out Westinghouse Nuclear (holds a ton of nuclear power generation IP). They let Korean Hyundai Motors buy out Boston Dynamics (arguably the most advanced robotics company in the world). They let Lenovo buy out Motorola Mobility, they let GlobalFoundries go to UAE-based Mubdala, Seagate is owned by a Singaporean holding company, and heck, the Chicago Stock Exchange is owned by a Chinese PE firm.
There are just many examples of American companies of strategic value being bought out by foreign entities.
So...my question to you is what were the alternatives?
IBM had largely been relegated to the past tense with PowerPC...so when it was sold the thought process was x86-64 was still supported with software by Microsoft and Hardware with Intel and AMD.
Toshiba is a Japanese company. Individual contractors in the nuclear field still exist, and with Japan nearly being a protectorate of the US (at the time) it was reasonable to have their ownership.
Hyundai and South Korea...same story as Japan. Additionally, DARPA could farm out stuff to anyone with a reasonable security clearance.
Lenovo buying out Motorola was...well, let's reasonably chalk that up as wanting cheap hardware from a country that could provide labor at rock bottom prices, with the assumption that their highest technology wasn't being manufactured in China...
The UAE...a country with oil...buying out Seagate...who have plenty of research facilities in the US and lots of bi-lateral agreements for that sweet sweet black gold.
Why is Intel different? Well...night vision goggles, missile control systems, computers, and about a dozen other things need Intel chips. AMD may compete...but mil-spec is a bother to get. Ironically, this is about the strategic needs unlike any of the other stuff. If you go through the above list, the concerns are primarily about having a competing option. There is none for Intel. There's no way to contract out their services, and no friendly country wants to pony up that sort of money.
Of course the two companies that are cited are US based...but the problem with that is that neither of them want the headache of more regulation being up in their business...because an inquiry into Intel branching out into the mobile chip space would be allowing too much discretionary observation of confidential information, but the US would presumably make this a stipulation of any agreed upon purchase.
This is also why an Intel buy-out would be little more than rumors. It'd come with a mile long list of requirements from the FTC, Military, and a dozen other governmental bodies. It'd make anyone wanting to own them have to jump through a thousand regulations to make any changes...and once they did they'd have to find some way to make things profitable. It's infinitely more feasible that Intel would be allowed to shed non-core businesses, and trim management, because based upon reporting they already have shed factory workers. That would be shrinking R&D, losing the GPU division, and removing the investor dividends (which they've already done). Intel's value on the stock market isn't a thing for the government of the US to concern itself with...and their directorship isn't likely to take any responsibility for the last decade of stagnant progress combined with huge amounts of money leaving the company as a one-two punch for executives paid in stock options to get a large chunk of money without it being apparent that their salaries were increasing...while their factory workers bumbled through miserable conditions where their processes sucked. I say they suck because of the yields reported...not as a judgement of anything else.