Yeh, I’m not going to be tactful here. People who make homophonic mistakes in writing are illiterate. I DGARA whether some “edumacationist” somewhere may call them “functionally literate.” “Edumacationists” are a disease and should be erradicated.
Misused words in writing due to homophonic conflation is simply due to poor literacy. Period. Using sounds or letter combinations that aren’t even words, due to mishearing (and never, apparently, READING) words is an even surer sign, if that’s possible. FarceBook is a particularly “rich” source of both of these sorts of homophonic errors. Most recent (as in, just a couple of minutes ago) example: “intack” (not EVEN a word) for “intact.”
Oh, the post title? I cannot (well, will not) even try to count the number of times I have typed (or thought) “gagamaggot” when I read or heard, “. . .taking a different tact” when “tack” expresses the meaning and “tact” does not.