This is always such a contentious issue.
I am a pedant. I have had jobs where proof-reading was an important part of the role so I can't help but notice errors and some of those errors make me wince.
I never correct errors on threads (unless a poster has been sneery about someone else's spelling and grammar and in doing so has made mistakes themselves) because I know it's rude.
However, it is clear that standards are falling and one of the things being lost is the ability to switch between different forms of language in different situations or contexts. That is a useful, and in some walks of life, essential skill. While I am sure that diagnosis rates for dyslexia have increased, I am equally sure that the majority of "would ofs" and the like that I see aren't down to disability, they are down to ignorance - in the true sense, not the pejorative - or laziness. When I see "does it matter if you know what they mean?" I can't help but think that yes, it does matter. We have a beautiful, rich and varied language that allows us to communicate with precision and it is being dumbed down.
I think many of the mistakes being perpetuated are down to social media; people see a word or phrase written down incorrectly that they've only ever heard spoken, assume it must be right and copy it and so it spreads. Quite often someone gets something very slightly wrong e.g. they think they mean word A but they spell it as word B which has a completely different meaning (for example I increasingly see "adverse" and "averse" used interchangeably). Yes, I can understand from the context what is meant, but it is still wrong and in some professional contexts would be judged harshly. Personally I would rather be told (politely) if I were using a word incorrectly because I would prefer not to make the same mistake again, but there doesn't seem to be any way of doing so without coming across as a dick.
Incidentally, many of the people I know with dyslexia - and I work in a university department, one of whose functions is to agree special exam arrangements so I encounter a lot of dyslexic students - are among the most vociferous against sloppy/lazy/kre8iv spelling, because it makes life so much harder for them to recognise the standard or correct form of words.