My understanding is that they aren't nearly as problematic as some other non-native plants though, like veldt grass, pampas grass, English ivy, sourgrass (African wood-sorrel), ice plant, Himalayan blackberry, cotoneaster, periwinkle, etc.
iirc the Dandelions we know are are native to Eurasia and are considered invasive across the US. They were brought over by early settlers for their health benefits
i have heard they were a garden plant but i dont know if that was an informal "spread the seeds and harvest where they pop up" or more of a row crop kind of thing...