Why should we have guardrails for guns? Works fine for me! It's legal in my state and I use mine responsibly! To suicide prone and mentally unstable people this is a deadly tool, it's seriously risky them. We should ban it!
Your and my ideas of individual freedoms are different. You (probably, based on your political leanings) believe that guns are bad and should be banned. You believe that particular freedom should be taken from individuals (but retained by governments). You believe that drugs are good and should not be banned. And the faulty logic you use is... "people should be able to harm themselves and that's why drugs should be legal. Guns harm others therefore they should be illegal." The elephant in the room, of course, is the death and damage caused accidentally to others by people under the influence of drugs.