We have all made spelling and grammatical errors. In fact, most of us make them often. That does not make them right, and it does not mean we should accept them as standard.
If someone makes a spelling mistake, any spelling mistake, whether common or rare, they should not be subject to ridicule for it. I do think there should be no issue with the POLITE correction of said errors.
Myself, if I'm spelling something incorrectly, I want to know it so I don't look like an idiot again and again.
As for 'leet speak, it's shorthand, it happens, and if you're typing on a cell phone, or you're trying to type while killing a monster in a game, it makes sense.
That said, I wish I had a utility that lets me (at my leisure) make the choice ... if it is not important enough to you to type it out, it is not important enough to me to read it.
Choosing not to learn correct spellings when you become aware you have made a spelling error or used the wrong homonym is a CHOICE. At that point it is not a mistake. It is a CHOICE to defy the status quo and use something that you know is harder to understand. In other terms, it is choosing to be irritating in order to avoid change, effort and/or admission of fault.