Your code, while looking like it could be every other, is based on math, so it will be even and odds as the query goes by iterations counting up. modulus 2 == 0 means even numbers in this sense (iteration / 2 has no remainder has to be an even number)
If you’re looking to have every 2 posts together you could do this:
<?php
while (have_posts()): the_post()
$count = $wp_query->found_posts; //counts all items in query
echo '<div>'; //starts first row
echo '<div>'.$content.'</div>';
if ($wp_query->current_post % 2 == 0) echo '</div><div>'; //ends row every other iteration
if ($wp_query->current_post % 2 == $count )echo '</div>'; // ends final row
endwhile
?>
post_count is the count of posts for that particular page, while found_posts is the count for all available posts that meets the requirements of the query without pagination.