There's nothing SPECIFALY wrong with Bore Butter/Natural Lube 1000. It's basically the same thing. The problem is when cleaning. You HAVE to use Dawn and HOT water to dissolve the grease/crud. If not, then rust will happen. I have an Investarms/Lyman that I used Bore Butter as both a lube and as a protectant in for a decade that has NO rust. But it was not easy. I HAD to use a lot of Dawn and lots of hot water to get it out of the bore at cleaning. Then WD-40 to disperse water, then after patching the WD-40 dry, a patch or two of Bore Butter down the barrel. I don't do this anymore. I've change hunting lubes to something more user friendly. That said......
I've mentioned this on the forum before, and Zonie (RIP) was the moderator and I had to be a bit coy with my statement then, but since no one seems to care now........
One of my good friends hunts with a Rem 700 Inline that he has owned for almost 30 years. It is a stainless steel model. But SS won't do much for rust and corrosion, at least not as much as modern man thinks. Someone told him at time of purchase to NEVER clean with water. He refuses to listen to anyone (including me) that has anything to say otherwise. He shoots loose Pyrodex RS at 100 grains and a sabot. He swabs the bore clean with Bore Butter patches and wipes the entire gun down with Bore Butter. The entire firearm is 100% rust/corrosion/pitting free. I know because I've examined it out of perverse curiosity. After seeing this for 3 decades, I can't honestly talk poorly about Bore Butter. Would I do this? Absolutely NOT!!! But he has and it has worked for him.
Bore Butter is not the DEVIL, but who knows what is?!?!