I know it's annoying, and I'm really sorry. But 80% of our account creation is spam on a bad day (a good day is only 40%), and of that, easily a third of it comes from those two VPN services -- and we're not the only ones who have that problem. (The visual captcha comes from our hosting provider, who uses data about abusive behavior across all the sites they host: if you're getting the captcha from them, it means you're on an IP that has been demonstrating sustained, consistent bad behavior.) We're trying very hard to use the least restrictive means possible to handle things, because we absolutely know that VPNs are an important privacy and security tool, but we're absolutely drowning here and we're not the only ones. Those two providers in particular are the source of so much garbage, internet-wide, that it really is important that they keep hearing from their customers that more and more sites are restricting their IPs and they really need to start removing abusive customers.