I've been a member for a long time and having backed 100+ projects I've seen crowdfunding go down hill significantly. Having been scammed, ripped off and taken advantage of on more than one project I'm more sceptical at times but still feel like there is a place for crowdfunding but the filters need to be in place. Since IGG and KS cannot block everything a place like BackerClub should have a code of ethics when it posts a campaign. Without this, BackerClub becomes a marketing arm for scammers and appears to only care about making money by promoting projects.
I would be willing to volunteer to help with this but at the least there should be some sort of vetting process before you accept a campaign to backerclub. At first you may lose some revenue but in the end you will be a place where backers flock to because there is trust that you aren't just creating a community for the sake of selling your mailing list to creators.
I agree you cannot stop scammers from getting in all the time but if you have a process to vet them out it would certainly be a start.