I've criticized PH for allowing voting rings and being a "black box" in general with respect to voting (see interview in Recode which had a comment from me: http://recode.net/2015/06/18/product-hunt-the-startup-kingma... ). The response to that interview is essentially "haters gonna hate," which means all attempts at offering suggestions to improve Product Hunt will be futile.
Yes, it still an echo chamber which I believe actually hurts the startup community because it incentives them to work on products which have zero value outside the echo chamber. It also incentives this bad behavior, and it has been spreading outside of Product Hunt which is why I'm upset by it.
If Product Hunt has enough community awareness such that they can tweet a GIF to every user who gets more than 100 points (seriously?!), then they have enough manpower to effectively punish and discourage vote manipulators.