foreach my $to_remove (@zu_loeschende_Adressen) {
   foreach my $idx reverse(0..$#alle_email_adressen) {
      splice @alle_email_adressen, $idx, 1 if 
         $alle_email_adressen[$idx] eq $to_remove;  
   }
}

use Perl6::Junction qw/one/;
@all_addr = grep { $_ ne one(@to_del) } @all_addr;

>>> all_addr = ['red', 'green', 'blue', 'yellow', 'orange',]
>>> to_del = ['green', 'yellow',]
>>> [mail for mail in all_addr if mail not in to_del]
['red', 'blue', 'orange']