Why, oh why, is Steam being impossible for me to sign up to?

The installer worked fine. I try to sign up for my son with his email and it tells me I have an account. I do the forgot password thing and it sends an email, then when I click the link it says I don't have an account.

Why would it send me the forgot password email?

I then try another email, follow the set up, click the email to verify. All good. When I set up my name, no matter what name I use it says available, but when I try to proceed it says Only use A-Z and 1-9, which each of the dozen names I tried was.

Then it takes me back and I try again. It tells me I have an account and to click the email verification link. I click the new link and it tells me I'm already signed up. Then I try the name thing again and the same nonsense happens.

And the extremely contrived captcha... I'm clearly not a robot or I would have given up due to the illogical nature of the process.

What the hell?