Ahhhhh, thanks for that! I'm German speaking, and I must admit I questioned the intellectual capacity of some people I conversed with, due to that. In German there is even a slur for it: "Deppenleerzeichen" (fool's whitespace). Now that clears things up.
Just a convention. I used to snigger at the English language convention of capitalising the next sentence in a letter/email after the address - after all, you're still in the same sentence, so why capitalise it. But, it's a conventional thing, so now I do it myself.
Eastern Europeans often drop articles because that’s (apparently) what they do in some Slavic languages. That’s a minor second/third-language quirk, not about an intellectual deficiency (lack of capacity).
Of course, some extra whitespace is even more harmless.
I think most people have these biases in one form or another. It's mostly a matter of your experiences I've found. Rural dialects especially trip me up. I don't know a lot of them personally, and most of the ones I see on TV are talking about.. rural stuff. Also, I think a lot of rural people who go to universities naturally end up toning down their dialects because they tend to be in the minority. So it's kind of rarer to see an academic with a thick southern accent. It will often be less pronounced. On the other hand Eastern European English accents have the opposite effect because most of the Eastern Europeans I've seen speak at length are chess grandmasters and physicists.
The only thing we can really do is try to notice these biases in ourselves and ignore them as best we can.
I never heard about the "Deppen Leerzeichen" in the context of punctuation, but always when German texts split up compound words with a space for no reason.
