The "pumpers" can't change the numbers or real information given by the sources, but stealing investors money vs "pumping" is not even close to a fair comparison. That would be like comparing a real estate agent and a thug robbing a retail store. Not even close!
Investment houses regularly upgrade equities to churn their house accounts. This is deceptive and stealing in my book. I personally know an honest broker that lost his job because he was not doing this enough to satisfy his boss. Just look at how many buy ratings some companies have had just before they blew up.