"These findings are consistent with the idea of marijuana as a "gateway drug." However, the majority of people who use marijuana do not go on to use other, "harder" substances. Also, cross-sensitization is not unique to marijuana. Alcohol and nicotine also prime the brain for a heightened response to other drugs52 and are, like marijuana, also typically used before a person progresses to other, more harmful substances.
It is important to note that other factors besides biological mechanisms, such as a persons social environment, are also critical in a persons risk for drug use. An alternative to the gateway-drug hypothesis is that people who are more vulnerable to drug-taking are simply more likely to start with readily available substances such as marijuana, tobacco, or alcohol, and their subsequent social interactions with others who use drugs increases their chances of trying other drugs. Further research is needed to explore this question"
Even drugabuse.gov recognizes that it's BS.
Speaks volumes too that you intentionally cherry picked the weakest link, the Gateway drug one. Not any single one of the health related ones.
I'd just like to point out that even you claim the links you posted are weak. ---