The vast majority isnt in the moderate, let alone high risk demographic though. So I dont get why there's this "GET THE SHOOOTTTTTT!!!!

" urgency for those not at reasonable risk.
The vaccines have also shown to reduce transmission which is also important in reducing the spread and getting to herd immunity
The vaccine has shown to be extremely effective at preventing severe cases for those at risk but nobody knows what exactly this vaccine could cause long term. And before you say "we dont know what covid causes long term" thats true, but with the vaccine, you can still catch covid so why risk both if you arent high risk?
Yes you can still have breakthrough cases but at the macro level most can vaccinated people can elicit an immune response to the point that they're protected, and 80% of the people that do get a breakthrough case don't spread it to a single person. It's more of about protecting the population as whole rather than the individual.
As for comparing mrna macromolecules to nitrosamines, Only the latter actually reacts to and damages DNA (which is what makes most carcinogens carciogenic in the first place). below is the mechanism for how a nitrosamine creates a crosslink with a base pair
Likewise if mrna was carciogenic then we would all be fukked due to the billions of mrna we create ourselves. Same deal with the phospholipids found int mrna vaxs. Not to mention neither one of them enters the nucleus (both the mrna and the phospholipids). It's just different chemistry and biological pathways.