I don't mean to claim otherwise, but I'd be interested to see what instances led to your observation.
It really is truly terrible support.
here's a source, since you're attacking and disbelieving everybody who doesn't love AWS: http://searchcloudcomputing.techtarget.com/news/2240203992/N...
The issue you mention (where you have to treat sg's as being immutable if you want them to work reliably) is another problem with the sg's.