Because these tools are often hosted on enthusiast forums or third-party archives like The Internet Archive

Packaged as a ZIP file, “antiwpav346” is typically distributed via file-sharing sites, forums dedicated to “cracking,” or underground repositories. The user is expected to extract the contents, run an executable (often disguised as an installer or a batch script) with administrative privileges, and reboot. Successful execution results in a system that reports “Windows is activated” in the System Properties dialog, albeit without a legitimate product key.

: [Note on the availability and helpfulness of documentation, support forums, or customer support.]

Furthermore, even if the tool itself is benign, the act of disabling Windows Update (often recommended by activation guides to prevent detection) leaves the system vulnerable to known exploits.