What goes into a person's mouth does not make him [displeasing to God], but what comes out of his mouth, that is what makes him [displeasing to God].
(The quote above has the word "unclean" replaced with the easier-to-understand "displeasing to God.")
As has been pointed out in many places by many theologians, ministers, pastors, lay people, etc…, this passage clearly shows that you do not goof up your soul or spirit by eating bacon, drinking soda, wearing lipstick, smoking cannabis, eating a mushroom, or drinking a Guinness Extra Stout.
Does this mean you should treat your body like a garbage disposal and toss in anything; snort, sniff, smoke, or inject anything with abandon? NO! The quote does not say it's pleasing to God to do anything to your body, the quote says you can not become spiritually "unclean" by what you consume.
Spreading lies, like telling people marijuana, mushrooms, etc… are intrinsically bad, is what makes a person "unclean." Telling people the lie that marijuana is not useful as a medicine or religious sacrament is what makes people "unclean." Saying that people are dirty or clean based on their urine is what makes a person "unclean." Spreading fear for the sake of income is what makes a person "unclean."
Now here is the part to keep you on the straight and narrow. Jesus told us we must deny ourselves, we need to "carry our cross." There are warnings in the Old Testament about falling into the temptation to live it up and spend all sorts of time eating, drinking, and being merry, and Jesus has a few of his own. Partying to get wasted is never advised, but it is not something our government should legislate; people need to learn to control themselves, not learn to hide from the holier-than-thou laws of humans.