Why drupal includes *.profile file on every page? I developed an installation profile that contains many various hooks. After an installation process, it is still included on every page, and all my installation hooks are executed. Please explain me why it happens, and by which way I can avoid including *.profile file after the installation.
This is a new feature of Drupal 7: install profiles behave like modules.

See #509398 : Install profiles should be modules with full access to the Drupal API and all it entails

Code that you don't want loaded during run-time should be moved to hook_install().

Edit - Xio asked about uninstalling a profile.
variable_set('profile', 'standard');
might work.