Maybe you think that those of us who call attention to typos and similar mistakes are being pedantic, or anal-retentive, just plain picky. If the meaning is conveyed, who cares about whether the words are spelled right or sentences are properly structured?
Nobody, if it’s a comment about your Saturday night outing at the local tavern with your buddies. But if it’s a business-related posting, it’s a concern for two reasons.
First, typos and misspellings suggest carelessness and imprecision, and those are characteristics most people don’t want in a company. If your post mentions “air condishoners,” I’m not going to hire you to fix mine. Those “unimportant” mistakes are the written equivalent of showing up to a meeting or waiting on someone at a store counter with a big glob of mustard on your shirt or food residue around your mouth. You may have the finest personal character, but humans react to visual impressions, and no matter how kind or talented you may be, the impression those things present is that you’re a slob.
Second, using the wrong words or incorrect grammar can inject subtle changes in the meaning of your messages, and you may not even realize it. The classic example on social media is the distinction between “Let’s eat, Grandma!” and “Let’s eat Grandma!” If that isn’t popping out at you, know that one suggests that Grandma is your dinner companion, while the other suggests she’s really the main course.