Most of the who use any kind of cannabinoid will say that it IS for medical (relaxation) purposes whether they've gotten a prescription for it or not. So other than those affects and its other proven medical benefits there really IS no reason to smoke weed. In fact just the act of smoking it rather than ingesting it in safer ways can cause health problems.

The medical benefits are unproven at best.

The idea of legitimate reasons for recreational activities is faulty on its face.

There are none.

I have no guesses at what would amount to "legitimate "in your view of the world.

There are no "legitimate" reasons other than medicinal.

Like sniffing Sharpies, it is something to do to rebel against societal mores.

It is a "feel good" pastime.

From ancient times it was a fun or religious substance.

Plantation owners gave it to Slaves to keep them compliant, so it was said. [Much like the Brits drugged the Chinese with opium.].

All I know is that the smoke makes my nose itch, uncomfortably. [I don't use it.]

Let’s ban alcohol except for medicinal purposes then. Same rationale you use.

It's safer than alcohol, it does not get people in fights, it's not a depressant. 🍑

1. It's fun.

2. It feels good.

3. It's none of your business.