I don't know, PHP used to be a security nightmare (or rather, it would encourage bad security flaws - I assume it is possible to write reasonably secure PHP web apps). Has that improved much? Yes, getting a site up and running is fast. Making it secure might be a lot less simple.
You can write secure apps in PHP. What I find unforgivable about PHP is that most of the code examples you will find on the web or in books is outdated and insecure. For example, a newbie looking for how to make a DB connection is much more likely to stumble on the mysql_* functions than on PDO.
