(answer: because the only kpi reliably communicated to ux and devs is the number of new signups and they don't actually care about providing the service of the application as much as they care about hockey puck user count graphs and gathering your data for resale and sending you e-mail newsletters)
@darth_mall @aparrish this is usually/sometimes because of enterprise/single-sign-on integration
as in if you type your organization's email address and it sees the domain part matches an SSO integration, it redirects you to the SSO page
a click is a bit much, I agree. At least some pages still just let you tab
@aparrish This pattern, and the one where you show the username and password fields one at a time with a superfluous click in between are driving me crazy.