That's what they're upset about.
If there were no use for 2D artists, then Stability Ai wouldn't be making an AI to replace them.
Key word here is: replace. 2D artists are not becoming obsolete - they're being replaced by a machine that was trained on their works without permission.
If you want to make an AI that does amazing paintings, and doesn't use human training data, more power to you. I can't compete with that. But if you use MY WORK to make a machine that's going to replace me, you do it under the cover of darkness and without permission - yeah i'll get pretty mad.
What happened to visual artists was more like Logitech announcing Logitech CoPilot and revealing they've extracted code from keylogging for the past 20 years.