Using Kodi we don't always get the usual advertising bumf that surrounds the selection and viewing of these movies when they're being made available on a website designed to rake in the ad revenue. I think a lot of these movies are flagged (incorrectly) as HD purely for the purposes of clickbait, by the time you've found out the truth you've had all those ads served up to you and the site has made a few pennies.
As I said, with Kodi we're lucky to be spared all that - apart from the Openload-type pairing - but we're still being fed the misleading meta-data by the sites. That's my theory anyway.
I tend to stick with a few add-ons that correctly identify HD\SD\Cam material like 123Movies, which also seems to go the extra mile to serve up HD content over everything else.