No more form-warning-messages at all, after module-activation

Can someone confirm this error:

1) Install an enable the Module Disable Message
2) Within the Disable Message Module Settings, just enable filtering (no other settings) or leave default settings (if filtering is already enabled)
3) (Clear or rebuild cache/s and) logout
4) Try to login with false password or similar, then, no message, f.e. "Unrecognized username or password. Forgot your password?" is shown

Seems to me, that after enable filtering such important system-warnings are per default filtered as it not should be (here all login/account-form-related system warnings)?

If so, the module isn't usable (especially for more comlpex sites, f.e. if you have to told your customer what exactly is wrong with his input).

Page and user level filtering options are no option, if you have a sidewide warning, you must filter.

Is this fixable?