Smoke v. THC - the physiological consideration

The last thing I want, is to piss off a bunch of closed-minded stoners who would never believe that their beloved weed would do anything to harm them. But it would seem to the objective observer that pot is not without its' drawbacks. I myself, am fairly liberal in my opinions and am quite in favor of legalization, but that does not prevent the question:
Why smoke it??
Smoking anything is bad for you. From marijuana, to crack, to banana peels, to a bbq grill even, any post combusted organic matter that deposits tar and other carcinogens on your lungs is BAD for your health.. -right?
The flagship answer to this question seems to be always readily available (and often quite heatedly and defensively) "There's never been a case of lung cancer caused by marijuana."
I find this nearly impossible to believe. Partly because it is often so poorly worded. In the life of a stoner who (let's be honest) has smoked more than just weed in their life [cigarettes for example] it would be impossible to discern which carcinogen was the straw that broke the camels back so to speak. I know of almost no one who has smoked marijuana exclusively their whole life. And for the few that do, good for them for not needing chemo - yet. Studies often rely on the user's reported use, which are undeniably unreliable. You simply cannot rely on the integrity of a stoner to determine the outcome of a study. (That's not a stab at stoners, it's universal - human nature) But on top of that fact, it would also seem that the amount of people who exclusively smoke marijuana, consistently for a large portion of their lives (like many tobacco users) is fairly limited. So much so, that it would be difficult for a study to create a large enough (and reliable enough) sample to make any sound inferences of any significance.
Studies argue, with conflicting results from equally respectable sources, as to the amount of carcinogens deposited from smoking weed. I will concede, that both pro and anti weed sources have reasonable arguments supporting their findings, but unanimously, every study I've come across finds that there are at least some levels of tar and other carcinogenic compounds deposited in the lungs from smoking.
Carcinogens! Cancer causing materials! So, even by definition, one must concede that weed at least has the potential to cause cancer - right?
I mean, millennia of evolution have geared the human species to avoid smoke. There is an evolutionary reason as to why you cough when you first smoke. Surely nature must know something that everyone else doesn't seem to get.

I'm open minded and am willing to hear other info/perspectives on the matter. I'm simply looking for answers as I have no moral qualms about marijuana itself. I mean no disrespect. I'm also avoiding any legal connection to the matter. I'm merely concerned about the physiological dangers of inhaling any carcinogenic compounds into an organ which has zero tolerance, defense, or ability to repair itself against such trauma.

But if I am correct, why doesn't everyone just vaporize or ingest weed orally [such as brownies] where the carcinogens created by combustion can be avoided? As it is reported to me, vaporizers are like, the 'everclear' of weed, and I'm told brownies last much longer than any smoked high. If not only is it more enjoyable to get high in these manners, but it is also exponentially safer for you physiologically, then why doesn't everyone do that? And worry about the potential molecular dangers of THC later.

Thoughts?

 

Fair enough. I would agree that people do not smoke weed with the same regularity that tobacco users do, but one study found that the length and depth of a single puff was extremely higher in marijuana users (understandably where pot users take the biggest, longest breath possible, whereas cig smokers take short, light drags) and that this significantly increased the tar left behind in the lungs

 

Makes sense. I get the instant gratification thing. I've only been high once in my life, and it was from a handheld vaporizer. I was told it cost around $250 but it was incredibly portable, shaped for a pocket, and easy to use. also, it seems like $250 isn't that much when you consider how much people spend on weed anyway, not considering potential costs for the occasional POM citation every now and again