I've never met a crackhead. But my guess is that more people went from alcohol to crack than from weed to crack. Alcohol is a much more of a gateway drug.
The problem isn't that you are being "that guy". The problem is you're being ignorant. Your anecdote about your friends from high school and college is just that, an anecdote. Anecdotes shouldn't be used. Millions and millions of Americans, and quite frankly humans, use cannabis responsibly and don't just sit at home and do nothing. It's definitely less harmful than alcohol.
People like you, who are stuck in the past with dated views that have been proven incorrect, are the ones who hold back our society, not people who smoke weed.