my theory--most bots are just like little soldiers defending the frontline,assuming estimates are correct 55-70% of all trades are electronic they are certainly not just hedge funds.
some stocks are held under the protective stewardship of a broker desk as a frontline defense against attack,yes there is a legitimate argument for algos however there is a big argument against the aggressive use of algos.
it would be fair to say confidence in markets has been substantially eroded by the misuse of algos.afterall they are a big part of the gfc and so far no real resolution has come forward --just more regulatory oversight and some prosecutions