Bring publicly viewable doesn't make them public domain. Bring able to see something doesn't give you the right to use it for literally any other reason.
Full stop.
My gods, you're such an insufferable bootlicking fanboy of bullshit code jockies. Make a good faith effort to actually understand why people dislike these exploitative assholes who are looking to make a buck off of other people's work for once, instead of just reflexively calling them all phillistines who "just don't understand".
Some of us work on machine learning systems for a living. We know what they are and how they work, and they're fucking regurgitation machines. And people deserve to have control over whether we use their works in our regurgitation machines.