“So why can’t you understand that Rabbanim feel it’s equally important- if not more so- to ‘ban’ things that are dangerous for the neshama?”
This argument is circular. What is the body if not a vessel to enhance the neshama? One’s purpose in life is to fulfill mitzvot and do tikkun olam, which is impossible if one is physically ill. Smoking is prohibited because a person who is lying in bed with lung cancer is limited in his or her ability to perform mitzvot. Similarly, smoking shortens a person’s life. Yes, we should be eager to get to Olam Habah, but the important thing is to maximize our time in Olam Hazeh so we can accrue as many mitzvot as physically possible. Simply put, smoking and other activities that endanger our physical health serve as barriers to Torah observance.