There used to be commercials that would show a guy smoking weed and his mother would say. Did you find a job yet, and he would say not yet. (because he was smoking weed) and then it said, weed will make you do nothing too. That is exactly what it does.
I'm going to address this because it's the part of your post that I actually take most issue with. First of all, a lazy person is a lazy person. Can heavy weed use exacerbate that issue? You bet. But, I'll guarantee you, that the lazy kid that didn't find a job wouldn't find one if he was smoking weed or not.
The other thing that is different from that commercial (and the timing of it) was that back then, the majority of weed being consumed at that time was cheap Mexican weed. Most of the pot being circulated at that time was an Indica strain. Indicas are known to make users lethargic (which is why Indica strains are now subscribed to patients with anxiety and insomnia issues) and more likely to make you "melt into the couch". Sativa strains are actually a little more "psychoactive" and are more effective on the creative side of the brain and are often used as a more "social" strain. I don't use as much as I used to but I had a great Sativa strain about a year ago and I can tell you that the LAST thing I wanted to do was "sit on the couch". The downside to Sativas is that they can make the brain a little overactive and can create the anxiety and paranoia that
@Trouty described earlier (actually he said pot either made him lethargic or paranoid. Which means whatever he was smoking at any given time was too heavily strained one way or the other). Marijuana use and development is much different and complex today than it was in the "find a job" campaign of yesterday. Chemists and botanists are working hand in hand today because of the advancement of medical use and are fabricating strains and hybrids that are 100 times more complex than the Mexican **** that Americans had been consuming for decades because, quite frankly, they can now.
You ARE correct in the assertion that ANY chemical that you ingest on a regular basis will change that person in one way or the other. That's, objectively, not debatable. However, the assertion and assumption that anyone who smokes weed is automatically "lazier" is rife with ignorance on the subject. That, my friend, is also not debatable.
Have good day, my brother, and enjoy your wine.