Those "oversized undercompressed" images are there for those of us that want them.
Nothing grinds my gears more than selfish pricks that expect all of us to lose out because they want compression.
If you want them in your games that's fine I never said you couldn't have them, but i think there should at least be options. That's what these generous individuals provide. I don't see the harm in thanking them for their hard work.
The other part of my comment was pointed at the net in general. Which abounds with ridiculous image sizes. On this site the icon next to "Like" is 18px, on others it can be 128px 512px I've even seen them at 4096x4096 all for an extremely basic icon displayed at roughly the same size on your screen. It serves no purpose. So yes, as a programmer who spent years optimizing software I find this waste of resources annoying.
On the opposite end of the spectrum we have images that are 1080p or higher being displayed the size of peoples sig banners. If you want to link to a separate full size image fine, but don't just scale a massive source down to a tiny size. Not only does increase bandwidth for both the user and the server, it distorts the quality of the image. We invented thumbnail images for a reason.