Well, it pees me off when people ignore the content based on the grammatical errors, and spelling errors.
I'l go into a bit of detail why, I don't have a learning disability, though I know people who do and have close friends who do, and they often have worse spelling then me, its understandable, and I help them often with there spelling, that being said, I'm awful at grammar and spelling, well bad for my age that is, being 18 I should be able to use correct grammar, and spell most things.
A lot of my spelling issues, are related due to my hearing impairment, that being said, I had a terrible primary school education, the school I went too sucked quite bad, most people who came out of there had awful spelling, and I mean awful, I could barely spell basic words, my spelling has improved massively since the last 5 years, due to me reading very often and teaching myself how to spell in small ways, I can spell most words but at times, I sometimes forget how words fit together, because I spell things how I hear them, the English language is quite confusing.
I myself could be dyslexic, but its mostly with spelling words or visualizing them, sometimes I would spell basic words wrong, and see them differently or when I don't write for a while, I accidentally write numbers in reverse, if that makes some sense, I can't explain it, but I can read on a above average level, I've always been a very good reader, some people are stronger in other areas.
I understand where you coming from, it does irritate me when some people cannot spell basic words, but I can also understand that not everyone thinks the same way, and isn't a real reflection of there intelligence, some people just either have some form of dyslexia, hearing problems or a learning disability, that being said, I can understand how both ends feel.
What does pee me off though, is I could write something very meaningful, have one spelling mistake, people either ignore the content, insult my intelligence, or call me retarded, which does drive me to the point that I don't even want to bother expressing my thoughts online anymore because some people like to pick at the smallest things, and make your life hell, just for forgetting a comma or using the wrong form of the word, I wasn't ever taught it in primary school that well, and kind of self taught myself most of what I know, I've come a long way.
What i really dislike is those people who just ignore content due to spelling errors or a grammatical mistake, I used to run a blog back in the day, and it flopped due to grammar nazis trolling me, compared to some, my spelling and grammar isn't even that bad either, a huge portion of the internet are grammar nazis and that does pee me off, I often do have difficultly mostly with grammar, it's not my fault, I find it confusing, because a lot of the time, the rules make absolutely no sense to me what I mean is things like.
Two, too and to, there, their and they, It's like what the hell half the time.
I do feel like those who have trouble spelling, do get discriminated against a lot, what I mean by that is people will ignore anything we have to say, if there are spelling mistakes, It does drive me nuts, because it does take me a lot of effort to write and check though it, a lot of the time, from what I've seen a few friends go though is that a lot of the time there spelling is so bad, that even spell check won't pick it up, I'm not even kidding, when I was younger, I use to have the same problem, and It is very frustrating because even if you google search the word, you can never find the correct spelling of it.
The best way I could explain this, is if you spelt things very wrong like exceptional: extpectinel, exmentalient (excellent) It will show up as wrong, but it will never find the correct spelling for you, and is a lot of the time, a pain.
That being said that is just my thoughts on this, that being said, I too get peed off when there are so many mistakes in someones post, however most people aren't doing this on purpose, and a lot of the time, they don't have someone else to help them point out what the word is, some people spell words that bad that even spell check won't even find the correct form of the word, often its close, but its way off, and yeah, its not perfect yet, what I'm thinking is sites could start integrating things like text to speech for dyslexic people and making text bigger, I think it would be a major improvement for most sites tbh.
I don't mean for any of this to be taken the wrong why, I'm just explaining my personal thoughts on this subject, I'm just explaining how I feel about it all.