my $word = substr $str, $-[0] + 10, $+[0] - $-[0] + 10;

There seems to be a typo there:

my $str = 'Hulk hate classless system with means of manufacturing give
+n to working class! Hulk crush puny Marxists!';
if ($str =~ /Hulk hate \w+/) {
    print "\$-[0] <$-[0]> \$+[0] <$+[0]>\n";
    my $word = substr $str, $-[0] + 10, $+[0] - $-[0] + 10;
    print "word <$word>\n";
}
__END__
$-[0] <0> $+[0] <19>
word <classless system with means o>
[download]

That +10 should be -10.

Anyway, the reason I'm replying is not this, but to suggest some typeglob aliasing to make the code a tiny bit easier to read:

*starts = \@-;
*ends   = \@+;
our (@starts, @ends);

my $str = 'Hulk hate classless system with means of manufacturing give
+n to working class! Hulk crush puny Marxists!';
if ($str =~ /with means of \w+/) {
    print "\$-[0] <$-[0]> \$+[0] <$+[0]>\n";
    my $word = substr $str, $starts[0] + 14, $ends[0] - $starts[0] - 1
+4;
    print "word <$word>\n";
}
__END__
$-[0] <27> $+[0] <54>
word <manufacturing>
[download]