I believe the first isn't true and the second is: people comment and move on.
1) Browsers have spell check. One of my general rules is not to make a web site more complicated by re-inventing features that exist in the browser.
2) This is an international community, with varying English language abilities. People misspeak, misspell, and have incorrect grammar. We should be forgiving of such things in order to respect that we are not all native English speakers.
It's also a helpful form of meta-communication in that often you can tell who is or isn't a native English writer, and adjust your replies accordingly. (Not to be mean or anything, but just to limit reading level or vocabulary.)