Poor you. I'm betting this is only annoying for those with a gazzillion accounts they're farming. Jusy click the stay logged in button. I've probably only ever logged in a handful of times to this site over the years I've been here.
I think you aren't right. Many people who have single account logging out of forum every time when they leave forum and then they have to solve captcha every time when they want to login again. That's not case for me, because I always stay logged in. But I experienced how hard and annoying Recaptcha can be and it can take few minutes (not seconds) to solve it. We have to solve Recaptcha on many other bitcoin related services - exchanges, faucets,and all otger types of projects. After multiple attempts to solve Recaptcha in short times, often it becomes very difficult and it's problem not only for account farmers.
But as theymos said, other captchas can be easily bypassed, sowe have to struggle with annoying Recaptcha :/