Mostly the trick is they're comparing lossy to lossless compression which doesn't even make any sense.
They're not actually confused here. It's a writing style, where you pose an interesting problem/scenario, then explain it.
When good expositors choose motivating questions, say like 3 blue 1 brown, they don’t usually make apples to oranges comparisons. The best examples motivate while making sense before and after you learn.
> This concept of throwing away bits you don't need to save space is called lossy compression. H.264 is a lossy codec - it throws away less important bits and only keeps the important bits.
> PNG is a lossless codec. It means that nothing is thrown away. Bit for bit, the original source image can be recovered from a PNG encoded image.