Well, starting from the top: It is indeed incredibly rare that you see an US program linking US made bombs to any given atrocity. So why this particular atrocity has made it through the fog is indeed a puzzle. Especially since we have heard barely a whisper out of Yemen in the last three years.

It also strikes me a bit of the line I have heard a number of times, of how every bomb every dropped by a US plane or ally somehow managed to hit a baby formula factory.

Bombs dropped out of US planes are basically a weather condition in half of Africa and most of the Middle East. Of course you only hear about those that hit weddings and baby powder factories. And even those rarely score half the column inches that a dude pulling a knife at the Tower bridge does. I don't quite get this line?

Now how this is particularly outrageous? Well, I'd argue that Yemen is one of the most outrageous things going on today. The UN estimated something like half a million cholera cases, most of them untreated since the hospitals have been bombed and little of anything enters the country. There is also a good chance that a few million people will starve if the blockade isn't lifted. So we are looking at genuinely genocidal numbers. I have no idea how good the numbers out of Syria are, since apparently there is only that one guy in Birmingham who tries to come up with numbers, on a foreign office salary, but 500k in total is the common number. Now in Yemen, no one has even tried to count since early 2016, but the UN writes about 7 million being on the verge of starvation.
And by my count the West provides the bombs, the targeting, the aerial refuelling and the US navy does most of the blockading.

"I am kind of curious why I've been seeing this particular narrative pop up here and there ...
.. I am a lazy pseudo-intellectual poser, but curious nonetheless."

Curiosity or lack of curiosity?
Knowledge, intelligence and understanding is fed by curiosity.

The leading nation of the past half century has managed to become a pariah state due to lack of anyone or institution to hold the USA accountable. It's not just the delivery of munitions and fighter planes, most of the time the US themselves were perpetrators of war crimes as we have witnessed too often in Afghanistan and Iraq.

President Obama promised to pull US forces  out of the war theater of Iraq ... he fulfilled his campaign promise. However the US changed policy by providing increased flow of arms to the "coalition" states and gave his blessing to fight the proxy wars for the empire [?] in Libya, Syria and Yemen.

Six nations in Europe established the EEC, an economic union to promote understanding and create a bond between nations we had been at war for over a century. The path of peace through economic cooperation between nations.

After the fall of the Berlin wall and downfall of Soviet communism, the promise of a peaceful world lasted for barely a decade. The attack on America by Saudi extremists of Al Qaeda in September 2001 changed the policy and role of the US and its NATO partners.

A monster was created by the Bush administration: War on Terror.

Bombing of populated areas create more resistance and seldom leads to "victory" over a people. War creates motivation for revenge and with Islam an easy road to radicalization. Fighters from Western Europe doing jihad by traveling to all the frontline states from Chechnya to Pakistan, Yemen, Turkey, Iraq, Syria and Tunisia. Spreading terror by a criminal enterprise of waging wars of choice for "regime change".

WAR MUST STOP - UK/US MUST END ITS WAR POLICY THROUGH NATO!  

Mission to Thwart Peace ☮️

I interpret the current mainstream media writings about US made bombs hitting Yemen as damage minimization. Blogs and such has been pointing out how the msm ignores Yemen and how the US is involved at every level of the war. By pointing at the horrors the msm places themselves in front of their critics, and by focusing on the bomb manufacturing they obscure the rest. And once the genocide becomes undeniable, they can blame primarily Saudi Arabia - or better yet, the Yemenis - and secondarily the bomb makers who in turn can do some whitewashing and promising to only sell bombs to good guys in the future.

But maybe I am just cynical, other explanations are possible. Perhaps some campaign to call out the weapons manufacturers has succeeded, in which case I applaud the campaigners.