That would depend on who & where those people were.......
if you mean in a book or newspaper, or as part of an exam paper when you may of worked your socks off Teaching someone the correct form, then no YNBU
However if you mean on here, which I presume you do, then yes, YAB V U .....
as already said, its chat board, & therefore attracts people from all walks of life & abilities, some may not be English, some may have disabilities, be ill, exhausted from sleepless nights with a young baby, or just had a rough day........others may not of had the benefit of good Schooling, or parents that have pushed home the importance of putting your head down & learning.........
it doesn't make anyone thick, & has already been said doesn't make their opinions or questions less valid
I have a CNS condition & because of this I often make similar types of mistakes,..... despite knowing full well ALL the rules of correct grammar, (Teaching family).....sometimes my brain says one thing, & my hands write something else......my brain then doesn't register this often until much later........
in the early days of being ill, it was something that really frustrated & upste me, & I would of been deeply bothered had I been pulled up for it, but these day it really doesn't bother me for myself as I think it says far more about the people who DO nit pick peoples spelling & grammar mistakes, than it ever does the victim, but not everyone is as thick skinned as I am, & I find it very sad on behalf of others
Some time ago I recommended this site to an Indian friend, very educated, & beautifully spoken Lady, she complained afterwards that she had looked, but felt very uncomfortable posting here, because she'd read people picking holes in peoples spelling & English Grammar..& she felt she might be attacked as she wasn't confident in her written English.....yet she speaks better than some English people I know,...
I was surprised as until this week I had never been on a thread where that had happened & then I was rounded upon, on another thread for similar such mistakes, by a group of so called "Teachers" & I have to be honest, it left a bit of a nasty taste in my mouth, & though I'm sure the involved posters have a valid role to play here, I doubt I'll ever put much value on anything I read by them again, because where as it didn't actually bother me personally, I can't now see them as anything other than a group of bigoted, insecure, harpies