Speakers haven't 'seent' the harm of casual language(It's short … it's better for you to read it than for me to summarize it.)
The piece caught my eye mostly because it deals with a common linguistic phenomenon that's not so common as a peeve: Many speakers simplify final consonant clusters, so that -nt is pronounced as -n, for example. So, dent gets pronounced as den. (Let's just leave aside for the moment the huge number of speakers who pronounce it with a glottal stop — that's relevant to the broader structural picture but not of immediately concern to my point.) A lot of research by sociolinguists has shown that people do this more often in words like dent that happen to end in the pattern and less often when the -t or -d is marks past tense, like in went, sent, and so on. For non-linguist readers, Winston Bayé is observing a hypercorrection, that is, where speakers who do this simplification are aware that they do it. They try to avoid it, but ending up adding a final consonant where it wouldn't normally appear, like seent for seen or spunt for spun. This bothered her enough to write a piece about it, so she talked to some linguists who make the usual points about informal speech and so on. (It's interesting that hypercorrection is really not about casual speech in some sense.)
The piece starts out feeling like it's going to be a rant about a peeve, but it seems like over the course of the article you can feel how Winston Bayé is actually wrestling with the notion of socially charged linguistic variation: We have good reasons for using distinct and distinctly non-standard varieties, but we can pay a price for it. She remains really concerned about the latter point but seems to get the former point. I don't know how journalists think about such a tone, but I find it kind of refreshing to see what's in some ways an opinion piece that lays it out that way.