I get the impression it's more because the bidbot owners are getting rich off people not understanding the math behind it... and the fact that the reward pool is supposed to be shared by everyone. Basically, there is a fixed amount of Steem to be rewarded to content. The "best" content should get the most rewards... however, every time someone uses a bid bot, that person is effectively stealing a higher portion of the reward pool from everyone else.... especially those people that put hours into a post or video.
The thing is, bid bots are so popular that they aren't providing a positive ROI, especially after the 25% curation is removed. So, the only winners are the bid bot owners... literally everyone else in the platform loses.