so they sell a person 200 SBD worth of votes, this is pure profit for the bid bot it can certainly reduce the price for its vote to levels that will please the user say turn that 200 into 80

No it can't. because the delegators want an ROI and they can go and curate for more than that. the curation rewards go to the bot and can be distributed but the buyer isn't going to pay the same as now, they are going to be paying less. introduce a few flags and that buyer loses the profit easily so, why buy? no many will wear a loss for long. the lower they drop the price, the more appealing curating looks.

As for downvotes, I don't think so, a retaliation round of downvotes by a bid bot would make a lot of the downvote lovers think again about downvoting them,

You think that is what they would do? :D I will gladly take their flags if that is their business model. THis is the first time in Steem's life that it really is up to the community. It is put up or shut up time.