Wikipedia has over 1,100 administrators. If you run afoul of just one of them, for example by disagreeing on a controversial topic, you are on death row, to be de-facto banned for life as soon as administrative leeway can extend far enough. This is known under the euphemism "indefinite block" and are given under the leeway that the block summary "Clearly not here to build an encyclopedia" provides, and administrators are reluctant to lift them due to peer pressure. And as soon as any future editor is identified as "block evader", they will be blocked again regardless of competence and good behaviour. It almost seems like they want one to run afoul, like in a mine field. Sure, many blocks obviously are reasonable, but some are not, or exaggerated, meaning a temporary and/or partial block would have sufficed. And anyone with harmful intentions would get blocked regardless of whether they were blocked in the past or not. In order to be honest, they would need to put that text on their front page. Ask yourself, why is "block evasion" so highly frowned upon there? How come newcomers who start with some unconstructive edits receive better treatment than experienced editors who just happened to run afoul of one administrator? Because "block evasion" would be an editor's last defense against administrative bullying. That's why it is not allowed.