Well the thing is that it's not an opinion though. Pretty much everything he's saying is all true.
You can't just determine if something is good or not without knowing the facts. Marijuana is good for you, it's not all bad. You can't say you "feel that it is not good in any way" when you don't know the facts.
And I'm pretty sure sooner or later, someone is going to mention that smoking anything at all is bad for you because of the carcinogens going to your lungs.
Has anyone ever heard of someone being diagnosed with lung cancer from smoking weed? Because I haven't. All the research I've read about it have said that it probably or might cause it, but there has never been a definite answer.