Just ignore them, any newbie account that has a lot of bitcoin knowledge or is overly negative/trolling is obviously somebody with an agenda.
I''m not sure it really ties to people trying to keep Bitcoin price down. I think this is talking more with accounts due to farmers like I mentioned in another thread: https://bitcointalksearch.org/topic/m.14774356 . But account farmers I think have goal of money through sig campaign or/and sales. I think this is majority we see.
I'm sure your right some have to do with pushing BTC down. But I think it's small subset of these "nuisance" accounts for lack of better term.