No one is asking you to change your view, they are telling you to stop shitting on our board with nonsense. Yes, they did, just like prior to maybe the last decade, there was a concentrated effort to portray weed as some demon drug that turned your kids into murderers or something else horrible (go watch Reefer Madness for some excellent anti-weed propaganda, you might get a few talking points out of it!). You should also go read about how pot was demonised in the USA by Nixon whom classed it as a schedule 1 drug in the first place.
Also I feel like you should definitely reconsider basing your argument on the slippery slope fallacy. After all, gay marriage is a slippery slope to inter-species marriage. While it doesn't bother me and seems almost as unrealistic as weed being the gateway to heroin at colesworth, I'm sure you'd piss off lots of religious people being in support of that slippery slope.
