I'm not a doctor, I just know that weed is relatively safe and it makes me happy, so I smoke it. That's really the only justification I'm going to give; personal happiness. Is it sad that I'm happier stoned than sober? Maybe. Is it a problem? Doesn't seem to be, things are going just fine.
As for the medical thing, from what I've read no one seems to suggest that eating it has any negative health effects. The smoking issues are from smoke. Basil would also probably give you cancer if you smoke it, that doesn't mean it should be illegal.
Edit: Did you actually read that link you posted? It seems to be very carefully worded. The main "facts" it states are
- Inhale more smoke? Yes, but I know that already, the question is about the smoke itself.Compared to tobacco cigarette smokers, people who smoke marijuana typically:
Inhale more smoke (two-thirds larger puff volume);
Inhale the smoke deeper into the lungs (one-third greater depth of inhalation);
Hold the smoke in the lungs for longer time periods (up to four times longer).
This results in the lungs being exposed to:
Greater amounts of carbon monoxide and other smoke irritants;
Greater retention of tar in the respiratory tract.
- "greater amounts of carbon monoxide and other smoke irritants" sounds spurious to me, given all the additives that go into cigarettes one would think it would have more irritants. One would expect such a statement to be backed up with some numbers.
- greater "retention" is irrelevant, because it doesn't address the question of how much tar there is to begin with.
It doesn't actually seem to be claiming any hard medical facts, just general common sense about the difference between taking small puffs and big ones.