Everybody knows the word 'typo', but few people know where it comes from. 'Typo' is short for 'typographical error'. A typo is a specific kind of error. It means that your error was not in knowledge, but in execution. You either hit a wrong key, didn't hit a key, or hit the right keys in the wrong order.
When we see the written word, we are incredibly harsh when it comes to errors, and we treat them all the same. We always assume that the writer cannot spell or doesn't know any of the rules of grammar. We never seem to consider that somebody may have just put their finger in the wrong place or was extremely tired while typing. No, instead, we're all a bunch of idiots who can barely communicate a thought.
Ease up on people with typos. We pretty much all make them at some point, so don't be hypocritical. And try to understand what it's like trying to communicate a thought effectively as possible, while also being as fast as possible. We can only catch so many errors when we read our own work and it is fresh in our minds.
On the other side, don't be an irresponsible typist. Proofread what you write. Even if not super thoroughly, give it a once over. Correct the big, major mistakes. Train yourself to type effectively and accurately. Don't justify your mistakes by saying that other people need to learn to accept your style. It doesn't work that way.
Not surprisingly, things work when both parties are willing to put in effort and compromise.