I see your point. However their profitability and supply can also be heavily influenced by downvoting. If I only look at a post in terms of proportion of rewards, the case for downvoting is easy.
The community is under no obligation to acknowledge the back-end transaction that facilitated the disproportion. The tenor of the argument I have seen so far, is that for some reason the onlooker should be obligated to consider that transaction when evaluating whether a post has been over-rewarded. The implication is that these bots are 'here to stay' and are a persistent 'feature of STEEM'. I don't subscribe to that at all.
I hope better places emerge to sink STEEM, and I hope the concept of bid bots will wither away and die. Either way I don't intend to facilitate their existence by participating, short of returning excessive rewards back to the pool. There are more than enough targets for my eyeballs that don't use them worthy of those rewards.