What i cannot stand is people who can do it, but refuse to out of laziness. Or because they want their content to be insecure on purpose.
This applies mostly to big orgs, so indie devs can have some leeway if it's too hard to implement.
(Raises guilty hand)
I run a couple of sites on my hosted server that are still http. They both sit behind a varnish setup and to be honest I just have not found the time to get it done. Usually when I mess with my configurations I lose a week to troubleshooting stupid stuff and I just can't bring myself to do it.
Again this really only applies to people in a comfortable position to do this and choose not to. The average developer is not my target here, it's the big guys.