I asked a question about another substance ormus along a similar line of thought. Stingray had quite a good answer.
And just a quick look at the downside of Meth

Long-term effects Methamphetamine use has a high association with depression and suicide as well as serious heart disease, amphetamine psychosis, anxiety and violent behaviors.
Methamphetamine also has a very high addiction risk. Methamphetamine also is neurotoxic and is associated with an increased risk of parkinson's disease. Meth-amphetamine abuse can cause neurotoxicity which is believed to be responsible for causing persisting cognitive deficits, such as memory, impaired attention and executive function. Over 20 percent of people addicted to methamphetamine develop a long-lasting psychosis resembling schizophrenia after stopping methamphetamine which persists for longer than 6 months and is often treatment resistant.
http://en.wikipedia.org/wiki/Methamphetamine

would be reason enough to make the substance illegal.
peace

If you ever loose anyone in your life due to a drug overdose you would be able to answer your own question.

My sisters youngest son died from a heroin overdose 10 weeks ago.

We dont have to ask why certain drugs are illegal Darrell.

We know why they are.

I don't know vey much about crystal meth but I do know that when our awareness is expanded we become aware of those parts of our being that don't serve us too well and as a result those dysfunctional behaviours no longer seem so appealing. If crystal meth users claim to have an expanded awareness, then why would they continue to use something that is so detrimental to their mind and body? I have a feeling the expanded awareness is either very fleeting or just an illusion.

You may be voted off the site, your question not part of what we are about. Ursixx gave you a down vote. Dude it's made with battery acid. I am giving your question a down vote as well.