(Never enter your real password into a password checker In their defense, it's stated pretty clearly that you shouldn't enter your real password and that this website allows you to test the "type of passwords" you use. They could use the fact that it's over HTTP to teach a second lesson in the results page about HTTP vs HTTPS, and warn the user again that he/she should stopping using that password immediately.
Most people wouldn't even know the mistake they've made and are probably sending the results link on too.