TLIK – the difference here is that it’s not just a halacha issue where there’s a chumra and a kulah, and you’re astounded at how otherwise very scrupulous people can be so lenient on thus shaalah.
Aveirah gorerea aveirah. If they were doing something halachikally wrong, it would spill over into their other practices as well, but as you noted, it doesn’t.
Let’s look at it from a bochurs perspective. The gedolei olam, people on whose every word we hang, people who we’re medayak in….almost all of them smoked. Some did even after finding out it was harmful; perhaps the boost it gave their learning (which it does) was more important; nevertheless, no gedolei yisroel encouraged it. Some already discouraged it in Europe, including the heiligeh chofetz chaim. There are still a few extremely choshuv roshei yeshiva who smoke. Smoking isn’t evil, it doesn’t display a bad midah or lack of yiras shomayim….it isn’t much different halachikally from eating a case of donuts everyday; actually, the donuts are worse, because it’s just a taavah, while smoking has mental benefits… it’s a stimulant which helps many people focus. I have never smoked, nor do I ever intend to, but I’ve known too many ehrliche yidden who do to be able to dismiss it out of hand as some sort of aveirah.
Comparing it with a device of clear ruchnius destruction is twisted; smoking was also not forbidden by ‘tons of poskim’. To my knowledge, the only body of ‘poskim’ who all of the sudden woke up and decided to forbid something was the RCA in the early 2000s. They let the internet, television, movies, intergender relationships, tznius, hair covering, and all manner of wanton sinfulness fester in their communities…but smoking!! Out come the payos – iz doch an issur gamur, venishnartem!! They also are the same types who isolate themselves from covid yet allow the diseased outside world directly into their souls, imbibing repulsive avodah zara, shfichus damin and gilui arayos without a second thought….and they expect us to take this ‘psak’ seriously? They also ‘paskened’ bot too long after about climate change….these wre are the self righteous, preaching to the choir activities of the largest branch of modern orthodox rabbis.