Really good question. If I had to assign cause, the reason is that there are just more H&H guns out there than most other brands and they were typically (but not always) higher grades that the authors generally wrote about, so tales of their exploits and maladies were over-published.
How I'd go about breaking this down is as follows:
1.) Big floppy red shoes are for clowns. Clowns buy 458WM double rifles. (and 416s, and any other rimless) They ALL fail eventually because the ejectors have tiny pins hoping to grab the belt. On their best of days with a clean gun and a cool temp hunt, you might get ejection. The fact H&H made a bunch of them (Did they actually make them, or did schmucks convert guns to them when they couldn't find the correct rimmed ammo in the 1960s?) At any rate, clown guns deliver clown results.
2.) PHs are not gun maintainers. Feel free to give me the exceptional case of a PH that is great with maintenance, but the stereotype is 98% true a a rule. Guns going off face exists everywhere. In America, I box up a gun and for $200 they tig weld up the hook, dress it down, and put it back on face. That doesn't exist in Africa, they just keep shooting dangerous guns. I can't tell you how many PHs reply when I call them on their terrible guns "oh its fine, the forend tightens up the barrels, see"... yeah, I see a dead man walking. The PH on the whole also has a really terrible logic fallacy that was taught in Africa: "Nothing I have is unsafe because everything worked the last time I used it". They cannot wrap their minds around the difference between past performance and future results. They don't replace thatch when its rotten, only when water comes into the home. They don't replace bald tires until they go flat. They don't fix off-face guns until they blow up.
One last incendiary comment: a lot of the H&H guns aren't really H&H guns. Almost all guns were made in the white by W.C. Scott or Webley, finished by them as well in the low and mid grades, final engraving, stocking, and regulation of high grades done by the famous retailers. When people drool all over H&H guns as though they are the greatest thing ever, I chuckle.
H&H didn't even have their own gun works until 1898 and they were covertly having much of their guns made elsewhere for a great period of time thereafter.
So I don't buy it that H&H were problematic double rifles going off face, otherwise ALL double rifles would be going off face because damned near every one was made by Scott or Webley whether they engraving said "Holland" or "Jeffery" Or "Army Navy" on them was immaterial.
So there, I've insulted rimless double rifle owners, PH's with their shoddy maintenance, and H&H collectors that own pedestrian double rifles they paid 5x more for because W.C. Scott engraved the word "Holland" on them and had them proofed in London instead of Birmingham to scam a Lord 140 years ago.
