Ah that's a fair question! So yes there is a degree of grey area; all the images here are from asset archives found on archive.org or other online sources, so they already exist out in the wild.
These are from asset/stock collections though, the original idea was that you would get a CD with textures on it, and you could freely use those textures in your projects; so they were intended to be used and included in projects.
Many of the CDs were handed out for free, some were included with software and others were sold; but of the ones that were sold, none are still available for sale and most of the companies that made them are gone, ADDITIONALLY most of these assets are too low res or low quality for modern games; I cant imagine a large AAA company using textures like this.
Long story short, these textures are really quite obsolete, but I think they are super cool. So this site is more like a personal project honoring them. Iv also resized and compressed most images, so if you want full res originals you'll have to go and get the original CDs, but for indie and web projects these lower res versions are perfect!