If you do them seated with a barbell, you WILL eventually fuck up your shoulders and back. Standing is a different story. Standing presses allow you to properly use your trunk to stabilize your spine, provided you don't do them like a fucking moron. That being said, if your scapular motor patterns are all fucked up and retarded, or if you have a congenital predispostion for bad scapulohumeral angles (lanky ass arms and narrow shoulders), then you are better off using dumbbells/kettlebells. But for the love of God and all things holy, don't take them out of your program entirely. Just don't train them like a "bodybuilder"; you can get all jacked and swole without training to failure.
I don't post what I do for a living much, but I am a Certified Strength and Conditioning Specialist as well as a Corrective Exercise Specialist, I work with both high level collegiate athletes and post-reconstructive surgery grandmas, and every single one of my clients utilize overhead pressing of some kind, and very little of it is done with machines. I work very closely with their physical therapists (if applicable) and any PT that has even looked at research articles over the last 5 years knows that properly incorporating the overhead press is key to long term shoulder health. The end.