"Grease is really oil thickened with a kind of soap. Do you really want to put that on your shooter?"
I've been using grease on my autoloaders since the 8th decade of the previous century.
Unlike many of the screeching doomcriers who predict that using anything other than a gun oil (IT MUST BE GUN OIL, OH GOD DON'T USE AN OIL THAT'S NOT SPECIFICALLY FOR A GUN! OH THE HUMANITY! doing so will not cause nations to collapse, dogs to cohabitate with cats, and swarms of liberals to cover the land, etc. etc. etc.
None of my guns have disintegrated, turned into inoperative blocks of rust, or otherwise failed to do what they're supposed to do.
When using grease on slide rails, use a light-bodied grease for best results.
As for Glock, it's intersting that they say use oil.
It's also interesting that they do not say "Don't use grease!"
In fact, I believe Glocks still come FROM the factory lubricated with... grease.
No wonder Glocks are so damned worthless and unreliable. They're lubricated with grease.
Bottom line.
For years I've experimented with lots of different kinds of oils and greases on my firearms -- revolvers, semi-autos, shotguns, and rifles.
I've found some that, given their properties, aren't great.
I've found others that have been very effective, and I've continued to use them for certain applications.
I've also found some that are labeled specifically for use on guns that are, frankly, not worth the extra 250% mark up that comes with their being packaged in a tiny bottle and labeled as "gun lubricant."
But the LAST thing I do is to listen to the screeching doomcriers who predict doom, gloom, and perdition if you use anything other than X product or Y product, and it MUST be X Gun product or Y Gun product.
They're wrong.