The problem seems to be that you are only looking for the first match (look_down is in scalar context) and are somewhat abusing the parameter processing of look_down to hook out the information you want. The better approach is something like:

use strict;
use warnings;
use HTML::TreeBuilder;
my $p       = HTML::TreeBuilder->new;
my @content = <DATA>;
$p->parse_content(@content);

for my $match ($p->look_down('_tag'  => 'div', 'class' => 'subsection'
+)) {
    my $prop = $match->look_down ('class', 'box_profile_info_small_hea
+ding');
    my $value = $match->look_down ('class', 'box_profile_info_small_co
+ntent');

    next unless $prop && $value;

    print $prop->as_text (), ' => ', $value->as_text (), "\n";
}
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which with your sample data prints:

 About Me  =>  you will know me better if you want to... 
 Who I'd Like To Meet  =>  i'd like to meet all the world... 
 Sexual Orientation  =>  Straight 
 Drinker  =>  No 
 Smoker  =>  Socially
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