tbh I don’t get why “speaking louder and slower to people who don’t understand your language very well” became a bad shameful white action performed only by bad shameful white people who should feel shame and derision and are morally and spiritually impure
talking slower and louder makes it easier for people to understand you. fucking half the people I meed on a regular basis mumble most of the time, and I’d sure fucking appreciate it if they talked louder and slower to me so I could understand them the first time instead of asking them to repeat three or four times, making them angrier every time
[le sigh]
It happened because “talking loud and slow” scans primarily as “talking the way you’d talk to a child,” and “treating foreigners like children” lies near the heart of the ugly-colonialist / ugly-tourist memeplex, for reasons that are mostly pretty reasonable.
Also because non-culturally-cosmopolitan Americans (in particular) occasionally lapse into the mindset of thinking that of course everyone in the world speaks decent English, or should…and, thus, that language-barrier problems are in fact problems of stupidity or obduracy, which can be solved by making the English communication sufficiently simple and hard to ignore. Unsurprisingly, non-Anglophones find this behavior unpleasantly condescending.
None of which contradicts your basic normative point. Speaking loud and slow is often useful. And even at it’s worst it’s mildly obnoxious in a provincial way, which is not the same as “horrifically shameful evidence of moral bankruptcy.”