You are much too believing. You've got to be more skeptical. Who, who believe smoking was a good thing 50 years ago? A couple of cigarette companies promoting the smoother taste with less coughing. 100 years ago and more, people called cigarettes 'coffin nails'. "People" knew smoking wasn't healthy, they may not have known exactly, but they knew.
Second, you're taking the word of one politician on what marijuana does to the lungs. This politician is NOT unbiased, he's NOT a scientist, doctor or epidemiologist and certainly hasn't read the literature on the health effects of pot.
You have to realize that drug prohibition is a leftwing program, that has gone on so long, that it's been adopted by conservatives as their own. The Left lies. When in doubt, remember that the Left lies. Polititicians lie. Do your own homework.
In over 30 centuries of known human consumption of pot, there are zero known deaths. If smoking pot is bad, then people can eat or drink it.