The bidbots bring in more investors into the steemit ecosystem as more people can buy large amount of steem and power it up. Check the largest power-up for last month, 60% were vote sellers which is a good thing for steem.
The more steem that is locked up, the scarce steem becomes and the high the value when the demand for it comes. I don't see anything wrong with selling my vote.
RE: Steemits Bidbot Business Income Analysis April '18