are pocket pull threw sharpeners really that bad for a knife?

Yes, they carve the blade, to the shape needed. That's removing metal. It can't be replaced. At the very least, try using a lansky sharpener. It's cheap, and gives razor Sharp results. The edge pro, is much better, but costs more. Or if you're lazy, use a paper wheel, on a bench grinder. But unless you're sharpening a machette, the carbide blade sharpener is no substitute for proper sharpening.

Yes! The ones with carbide blades will ruin a blade. The ones with ceramic rods don't work all that well. When I sell a knife it comes with explicit instructions not to use one. A gentleman brought one back to me for repair, the edge was chewed up because his mother-in-law "sharpened" it.

Nope. They are not the best but are better than a dull knife.

nn

No.